The children, a nine-year-old girl and a boy, 6, were taken to Rockhampton Hospital in critical conditions after a two vehicle crash at Yeppoon Road and Artillery Road about 9.40am Sunday.

The girl passed away in hospital and the boy was on Sunday afternoon being flown to Queensland Children's Hospital with life-threatening injuries.

One of them had been pinned inside a car with a serious head injury while the other suffered serious head and abdominal injuries.

Police say those children were with another girl 10, and an Emu Park woman, 40, in one car, while a 33-year-old woman and two other girls, aged eight and 12, were in the second vehicle.

They believe one car was travelling east on Yeppoon Road when it moved to the middle of the intersection, colliding with the side of the other car, which had been heading north on Artillery Road.

One child under the age of 10 was pinned by their legs inside the car by damage caused during the crash, a Queensland Ambulance spokesman said.

The other five patients sustained only minor injuries, and the forensic crash unit is investigating.

Australian Associated Press