Mother of crash victims pays tribute on what would have been her daughter's 18th birthday.

Marina Pink would have turned 18 today. But rather than raising a glass in celebration, the Brisbane teen’s mother is asking others to do so in her memory.

“Please go buy Marina Pink a drink in every GOOD bar of every town in every city,” Jaze Pink wrote on Facebook this morning, less than 24 hours after her daughter’s tragic death.

The 17-year-old and two of her six siblings – Jack, 19, and Destiny, 15 – were killed on Monday morning in a fiery crash near the northern NSW town of Boggabilla.

The family, travelling showmen who had reportedly been working in Dubbo, had been driving in convoy along the Newell Highway at around 6am. Their father, Glenn, in front; then Jack towing a trailer with a Pantech truck; and the two girls following behind in an SUV.

Investigations into the cause of the crash are still underway, but according to NSW Police, Jack's truck collided head-on with a petrol tanker, which then rolled on top of the girls' Landcruiser.

The driver of the truck escaped with injuries to his shoulder, but the teens died instantly.

When emergency services arrived, they found a distraught Glenn Pink collapsed near the fiery wreckage.

In her post this morning, Jaze wrote, "Marina, my darling, as bossy as hell! Party with your brother and sister, drink with the gods, Poppa Max and Prickly Pink, and all of our loves."

Also paying tribute on social media was Jack Pink's partner, Monica Watkins, who yesterday promised she would never forget the man who had become "my other half, the love of my life, my number one".

“I’ve never been so sure about someone in my life, not only did I just lose my boyfriend today but I lost my future,” she wrote on Facebook.

"You were so so so happy, we were both so happy, but without you now I feel numb, I don't feel happy at all. I just need you back Jack, honestly I just need you back."

The young woman wrote of their final moments together, an airport farewell.

"My last words to you were 'I love you so much, goodnight and drive safe tomorrow' and you told me that you loved me back and told me to have a good sleep," she wrote.

"I love you so so so much Jack and I just miss you so much. [This is] Not a goodbye, because I'm so sure that you will come and visit me in my dreams tonight.

"Fly high my angel."

A GoFundMe campaign in aid of the Pink family has been established, with more than $81,000 raised so far.