Two charged over boy's road crash death

Police have charged two people with manslaughter after a boy was killed when he was allegedly left in a crashed four-wheel drive on a regional Queensland highway.

Investigators say the six-year-old wasn't removed from a Toyota Landcruiser that left the Carnarvon Highway near Injune and rolled over several times despite two adults managing to free themselves from the vehicle.

The four-wheel drive, which had come to rest in the northbound lane, was struck by a passing truck and the boy died at the scene of the accident, which happened in the early hours of January 6.

After a year-long investigation, police on Wednesday charged the vehicle's driver, a 34-year-old Roma man, and a 19-year-old Imbil woman with manslaughter over the boy's death.

The man has also been charged with dangerous operation of a vehicle causing death, while both were charged with taking a protected animal.

They were allegedly returning from a kangaroo-shooting trip in the rural area when the crash happened.

Both were granted police bail and will appear in Roma Magistrates Court on January 17.