News in 5: 'Child abuse' videos on Snapchat; Lord Mayor quits; WBBL winners.

Warning: This article contains information about sexual assault and child abuse which may be distressing for some readers.

1. “He is dying tonight for sure”: Horrific Snapchat videos of Melbourne teenage couple’s “abuse” of toddler prompt police investigation.

Police are investigating claims of child abuse after a teenage couple shared disturbing videos of a young toddler being abused on social media.

According to 9 News, the videos, which were shared on Snapchat over the weekend, show a young male and female laughing as a toddler - who they say is their child - struggles to breathe with a plastic bag over it's head.

"We're not child abusing them, were just teaching them discipline," one of the teenagers can be overheard saying in the footage.

"Making sure they're not dead, but then... they can't breathe."

Another video shows a young boy crying as water is poured over his face. The video is captioned, "he is dying tonight for sure". Another caption reads, "I can't believe he's steal [sic] alive."

In one video, the pair - their faces obscured by smiling emojis - defend their actions.

"That's my child, that's our child... you're not going to teach us how to treat our child," the teenage girl says.

"If I want to slap my child, I'll slap him as much as I want," the young man - who claims to be the woman's husband - adds.

According to 9 News, police visited a Melbourne property after being notified of the videos and found the child "safe and well".

Police confirmed they were speaking to a teenage girl about the situation, but no charges have been laid so far.

2. Robert Doyle has quit as Melbourne Lord Mayor after sexual harassment and indecent assault allegations.

Robert Doyle has quit as Melbourne Lord Mayor and is in hospital after being driven to the brink over sexual harassment and indecent assault allegations, his family says.

A by-election will need to be held after Mr Doyle, 64, quit the City of Melbourne on Sunday night, AAP reports.

His resignation comes after being admitted to hospital "on the brink of being broken", his wife Emma Page Campbell said.

"He is a good and decent man. I love him. And because I love him, to watch and share what he has been through in the last seven weeks has been agony," she said in a statement.

Mr Doyle also quit as the chairman of Melbourne Health and continues to strenuously deny the allegations.

"I am disappointed that Robert has been given no benefit of the presumption of innocence - a resort to foregone conclusions, and with none of the protections afforded even to those accused of the most horrible crimes," Ms Page Campbell said.

Mr Doyle was in December hit by claims of sexual harassment, indecent assault and misconduct, and stepped aside as mayor while Ian Freckleton QC launched an investigation.

Former Melbourne councillor Tessa Sullivan quit over alleged inappropriate behaviour by Mr Doyle against her and another woman.

A third woman in January claimed Mr Doyle touched her leg under a table and made offensive remarks to her at a Melbourne Health awards ceremony in 2016.

Victorian Health Minister Jill Hennessy ordered the Department of Health and Human Services to commission a separate independent investigation into the allegations.

Mr Doyle on Friday revealed he was suffering from stress-related "serious ill health".

K&L Gates partner Nick Ruskin said the toll the allegations had taken on his client "cannot be underestimated".

"Following allegations seven weeks ago, he has been through a period which he feels has lacked any semblance of natural justice, where the burden of proof does not rest with proving guilt, but rather with proving innocence," Mr Ruskin said.

The City of Melbourne found out about Mr Doyle's resignation via media reports.

"We will progress the conclusion of the investigation as quickly as possible and ensure the facts become known to all parties," it said in a statement.

3. Children as young as three are sleep deprived after spending too much time on smartphones and tablets.

Many children as young as three are sleep deprived because they've spent too much time on smart devices such as phones and tablets, AAP reports.

Up to 17 per cent of children aged three and younger own their own smart device, News Corp reports, and many are falling asleep at pre-school and their child-care centres.

A child health poll by Melbourne's Royal Children's Hospital revealed children spend an average of 32 hours a week or four and a half hours a day on these devices, with 43 per cent doing so at bedtime.

A paediatric doctor at Sydney's Woolcock Institute of Medical Research, Chris Seton, says the number of very young children with sleep issues was increasing.

At the same time, Federal Education Minister Simon Birmingham wants smartphones banned from classrooms, saying they are a distraction and "a platform for bullying".

The recent death of 14-year-old Amy "Dolly" Everett, a victim of cyber-bullying, has put the spotlight on the issue of access to social media and the harm it causes.

"There's almost no reason students shouldn't have their phones switched off and in their lockers while they're at school," Senator Birmingham told News Corp.

"Although learning to work with technology is essential, phones can be a distraction from lessons and a platform for bullying unless schools have the right policies in place."

If you or someone you know needs help you can call Lifeline on 131 114 or Beyondblue 1300 224 636.

4. The Sydney Sixers have thrashed the Perth Scorchers to win the WBBL Grand Final for the second year in a row.

Sarah Coyte hasn't ruled out an international return after inspiring the Sydney Sixers to consecutive WBBL crowns, AAP reports.

Coyte starred with the ball as the Sixers bowled out the Perth Scorchers for 99 in Sunday's final at Adelaide Oval.

The Sixers made light work of the run chase, losing just one wicket and securing the title with 31 balls to spare.

Coyte took 3-17, a week after returning to top-level cricket following almost a year out of the game while battling anxiety.

After collecting the player of the match award, Coyte said she was uncertain if she would press for a spot in Australia's Twenty20 squad for the World Cup in November.

"I don't know," the 26-year-old said.

"I really like the life I have now - I like my work and going home at the end of the day not having to pack the bag and go to the airport.

"But you never know what the future holds ... I'm just going to take each day as it comes."

Suffering from anxiety, Coyte quit cricket after playing 30 one-dayers and 40 T20 games for Australia.

She was only asked to return to the Sixers for last weekend's games after playing grade cricket in Sydney.

"It was a call of the blue ... I had a lot to weigh up and think about with my mental state, with work and everything like that," Coyte said.

"Part of me was curious to see what I still had left in the tank and if it would rekindle a bit of love for the game."

Triumphant Sixers captain and Australian stalwart Ellyse Perry said Coyte wouldn't be pressured to make an international comeback.

"To just slot back into the team the way she has is a true testament to her character," Perry said.

"I don't want to put any pressure on Sarah, that is entirely up to her. The most important thing is that she is enjoying whatever she's doing."

Perry struck the winning runs on Sunday, a sweet moment after missing the Sixers' win over Perth last season because of injury.

Perry and fellow opener Alyssa Healy ensured a trouble-free victory with a brisk 64-run opening stand from 10.1 overs.

5. Now that the holidays and hangovers are done, Australia has officially entered 'rehab' season.

First there was the holiday, then came the hangover. Now? It's rehab season.

A spike in Australians self medicating and over indulging during the summer holidays has left many seeking rehabilitation services, according to addictions experts.

While the reasons for lapses and relapses vary greatly, the emotional strain of Christmas holidays and the booze-filled festivities of New Year's Day, Australia Day and all the parties in between take a toll, AAP reports.

"It's really going to ramp up now," says CEO of Melbourne's DayHab clinic Nick Hall.

"People present for treatment when some sort of crisis happens - the holiday period, especially Christmas, is a difficult time for a lot of people.

"It's emotional, it's about family and many struggle because there's relationship issues."

Himself a counsellor of 16 years, Dr Hall says a reliance on alcohol or other substances is a symptom of a bigger problem - people not coping with emotions.

Nearly 20 per cent of Australians exceed the lifetime risk guideline by consuming more than two standard drinks a day on average, while alcohol remains the principal drug that leads to treatment (32 per cent), according to the Australian Institute of Health and Welfare.

Over summer, the mixture of family issues, financial stress and parties becomes a problematic cocktail that leads too many people to pick up drink after drink, Dr Hall says.

"Imagine being in the madness and trying to hold all your shit together," he says.

It's exactly this sentiment that drives people in droves to Sydney-based addictions counsellor Chantale Ishac, who says the post-holiday period marks a peak in referrals from existing and new clients.

"When kids get back to school and we get back to our careers ... instead of feeling refreshed to start the work year, people feel they are returning from a war zone," says the CEO of Addiction Intervention Services.

The addictions expert urges people to stop being in denial and ask themselves a few important questions, including whether they stick to the amount they promise themselves and whether their actions are damaging their mental health, finances, career or relationships.

Although people turn to many different "crutches" to self medicate, such as illicit drugs, gambling and prescription medication, Ms Ishac says alcohol dependency can go unnoticed because of the nation's drinking culture and societal normalisation.

6. Man accused of keeping a woman as a 'sex slave' for weeks in his Brisbane home.

A man accused of keeping a woman as a "sex slave" and repeatedly drugging and raping her at a Brisbane home over a number of weeks has been denied bail, AAP reports.

The 29-year-old, who can't be named for legal reasons, appeared in the Brisbane Magistrates Court on Saturday charged with 28 offences, including deprivation of liberty and six counts of rape.

He is accused of initially drugging the victim in the Brisbane CBD with the tranquilliser benzodiazepine on January 18 before taking her to a Fig Tree Pocket home, where she was held against her will until January 31, court documents show.

During that time the woman was drugged, raped, sexually abused and assaulted, police say.

"In short, the defendant has kept a young lady prisoner and sex slave for (a number of) weeks, drugging her and raping her repeatedly, with previous inclinations that would suggest the behaviour is something of a pattern," police prosecutor Mark Gorton told the court on Saturday.

It's alleged that during that period the man filmed the woman without her consent and distributed the footage.

He is also accused of assaulting her at a separate Brisbane address and was found by police in possession of the anxiety medication alprazolam and a mobile phone at a Kedron address on January 31.

The man's lawyer, Kylie Bell, told the court her client disputed the charges.

"I'm instructed that any sexual contact was consensual and there's a dispute certainly that any stupefying drug (was) being provided," Ms Bell told the court.

"The complainant left the residence on most days, he would drop her into the city, she would attend work, she would be collected in the afternoon."

The court heard the man lived in a granny flat at the Fig Tree Pocket address, where the offences are alleged to have taken place, with his parents and sister living in the main house.

In her request for her client be granted bail, Ms Bell said he had deleted the woman's number from his phone and had no intention of contacting her.

Magistrate Bronwyn Springer told the court she would refuse bail after considering allegations of previous complaints and photos and video footage.

Ms Springer said she was particularly concerned about a video of the accused having sex with the woman where "she can be heard telling him to stop".

"(Along with) the threats to upload videos of her, the threat to kill a woman with whom he was in a previous relationship, in my view the defendant is at unacceptable risk to further offending and of endangering witnesses," Magistrate Springer said.

The man is due to appear in the Brisbane Magistrates Court on February 26.

If you or someone you know is in need of help, please call the National Sexual Assault, Domestic and Family Violence Counselling Service on 1800 RESPECT.