The collision, involving three cars and a truck, occurred at an intersection on Banya Avenue in the Aura estate shortly before midday, News.Az reports, citing ABC.
A spokesperson for the Queensland Ambulance Service said the injured children were of toddler age.
Several witnesses, including tradespeople at a nearby construction site, helped the injured until emergency crews arrived.
One of the children was airlifted from the scene to the Queensland Children's Hospital (QCH) in Brisbane.
The other child was initially taken by road to Sunshine Coast University Hospital (SCUH), but has since been flown to QCH for further treatment.
Five other people, including a woman believed to be the children's mother, have also been taken to SCUH in a stable condition.
The woman, aged in her thirties, suffered head and chest injuries.
Another patient was a driver in his sixties who suffered a medical episode.
Investigators are working to determine if the episode may have contributed to the crash.
Resident Bimal Khanal was at the scene on Thursday afternoon and said he knew the family in the blue car.
"That's my neighbour's car. They are really good friends of ours, more like family. We are really in shock," Mr Khanal said.
"It's really tragic."
Police are warning drivers that significant delays are expected and to avoid the area.
