"He is a danger to himself." Grant Hackett's family shares concern after his arrest.

Former Olympian and Australian swimming legend Grant Hackett has been released from jail after being arrested at the Gold Coast home of his parents on Wednesday lunch-time.

Following the arrest at the Mermaid Waters address, Hackett’s father Neville told The Gold Coast Bulletin his son had been arrested over mental health issues.

“Grant’s got a medical problem and it manifested itself here this morning … He’s big and powerful when he’s not happy,” he explained.

“We decided he needed some treatment but there was no way he was going to go and get treatment this morning so we called the police.”

Eight officers attended the scene and were said to have found Hackett asleep. No one was harmed while restraining Hackett or taking him to the nearby Sourthport watch house.

His father confirmed that nobody was touched, nor was any property damaged.

“He was raving and ranting a bit ... He didn’t even make any threats but was not what you say is a normal person. It’s what I’d call a bit of a breakdown," he told The Gold Coast Bulletin.

Following the arrest, Queensland police told Mamamia, "Police have arrested a man following a disturbance at an address on Surfers Avenue at Mermaid Waters around midday today. There is no further information at this stage."

Watch: Grant Hackett being taken away by police. (Post continues after video.)

Hackett was released from the Southport watch house hours later, just after 3.30pm, without charge. It is understood he will now seek treatment in the nearby Pindara hospital.

The athlete's brother Craig spoke to Nine News on Wednesday evening, saying Grant was a "completely different" person.

"The Grant Hackett that Australia fell in love with, this is not Grant Hackett ... He is there in body but he is not there in mind, soul, or spirit," he explained.

"This is now a chronic problem and it looks like it's not going to go away in a hurry."

Craig added that the situation had reached a "dangerous" point with no clear outcome.

"He is a danger to himself, he is a danger to the community and poor mum and dad have tried to look after him so much. I'm concerned for their welfare," he admitted.

"To see someone who was so dominant and had the world at his feet to now, we don't know what is going to happen - it doesn't look encouraging."

Sadly, the reported arrest is not the first run-in Hackett has had with police.

Following the Beijing Olympics in 2008, Hackett announced his retirement from swimming after a golden career in the pool. At the time, however, he had begun taking the highly addictive sleeping pill, Stilnox.

Then in 2011, just three years later, Victoria police attended a dispute at the home Hackett shared with his now ex-wife, Candice Alley. Upon arriving, police found the house in disarray with furniture and possessions smashed throughout the apartment.

Six months later, Alley and Hackett announced their separation.

In 2014, Hackett was pictured walking around Melbourne's Crown Casino barefoot and in just his underwear, disorientated and looking for his young son.

Following the footage being released, the star was plagued by rumours that he had been under the influence of alcohol and/or drugs at the time of the dispute, and his family eventually staged an emergency intervention with the sporting legend which lead to a six-week rehabilitation stay in the US.

Following the stay, Hackett said, “It just gets to a situation in life where you’re not coping too well and you need to put your hand up and ask for help. I certainly got to that situation. And I feel proud of myself that I had the strength and courage to do that.”

Then in 2016, after announcing his comeback and failing to qualify for the Australian Rio Olympics team, Hackett was arrested once more after allegedly assaulting a fellow passenger on a Virgin Australia flight.

According to the passenger, who was sitting in front of the swimmer during the interstate flight, Hackett leant forward and grabbed his chest and nipple.

Hackett was met at the flight gates by waiting police, and following the arrest, footage of Hackett passed out in a wheelchair at the airport surfaced.

More information on Hackett's latest arrest to come.