LATEST: A mother and father from Ipswich who were trapped in their car following a horrific crash on the Sunshine Coast told their children to climb out of the wreckage and wait for help to arrive.
Their car was then hit by a truck.
The tragedy unfolded when a Subaru, believed to be driven on the wrong side of the Bruce Hwy, struck the family's red sedan about 10.30pm on Wednesday.
The Subaru's driver, from Rosemount, was killed.
The couple, who have been named as Tammy Boyce and Nathan Boorer, were understood to be on their way to Hervey Bay with their children for a camping holiday.
Ms Boyce, 28, is believed to be 28 weeks pregnant.
She was in a critical condition in the intensive care unit at Nambour General Hospital yesterday.
Mr Boorer, 28, was also in a critical condition and was airlifted to the Royal Brisbane Hospital late yesterday.
Details of how the collision occurred remained unclear last night.
There were indications the driver of the Subaru, a 54-year-old man, had either been travelling in the wrong direction for at least 5km or had made an incorrect entry onto the highway.
There were also indications the man was intoxicated.
The crash happened about 1km north of the Nambour-Bli Bli exit.
The red sedan with the family on board was flung onto the side of the highway, while the other car crashed onto a grass median strip.
A police spokesman said two children, a nine-year-old boy and a five-year-old girl, were told by their parents to climb out of the car and stand on the side of the highway where it was safe.
It was understood they had minor injuries, while their parents were trapped in the driver and passenger seats.
After the children had left the wrecked vehicle, it was struck by a truck travelling north.
When emergency services arrived on scene, rescuers had to remove the doors and roofs from both cars to get to the people inside.
Paramedics performed CPR on both the parents before they were taken to Nambour Hospital for emergency surgery.
The children were treated at the scene and also admitted to hospital in a stable condition.
Their grandparents came from Ipswich to be by their side.
Pictures show the family car had been packed with camping gear, including a tent, ice box, pillows and sleeping bags.
They had been on the road for about an hour and 50 minutes and had covered 150km.
It was understood the holiday was going to be the family's last getaway before school resumed on Tuesday.
Both cars were unrecognisable after the crash.
A 50-year-old male, a passenger in the deceased male's vehicle, was in a stable condition in hospital last night.
Investigations are continuing.