The Greyhound bus carrying 33 people and 4WD had been travelling in opposite directions near Gumlu, in the Whitsundays region on Sunday when they collided in a 100km/h zone on the Bruce Highway.
Police described the chaotic crash scene as "very, very confronting" with investigations ongoing into the cause of the tragedy.
The bus was heading to Townsville, around 1.5 hours from where the crash took place.
Seven people had been transferred to Townsville University Hospital following the crash.
Acting Chief Medical Officer Jason Yates said that three people had been discharged on Sunday evening.
Four people remained in the hospital, with two men aged 24 and 23 in critical condition and another two men, aged 27 and 51, in stable condition.
With AAP.
