Police believe 4WD towing caravan that crashed with bus, killing three passengers on Bruce Hwy at Gumlu, avoided contact

Three people died as they travelled on a bus that crashed into a caravan, with the four-wheel-drive towing the caravan appearing to have avoided the wreckage, Queensland police have revealed.

A woman in her 20s, a woman in her 30s and a 56-year-old woman died in the crash on the Bruce Hwy at Gumlu, south of Townsville, shortly after 11am on Sunday.

WATCH THE VIDEO ABOVE: Details emerge over deadly Queensland bus-caravan crash.

Seven people were taken to hospital, including a 23-year-old man and 24-year-old man, both of whom were in a critical condition.

They remain in intensive care in Townsville University Hospital on Monday.

Police have declined to speculate on the cause of the crash, citing the ongoing forensic investigation, including questions about whether driver fatigue or road conditions contributed.

But in a statement on Monday morning, police revealed it was believed the “caravan and bus collided”.

It’s not been revealed how the four-wheel-drive avoided the collision.

Superintendent Graeme Paine described it as a “very complex investigation” that involves forensic examinations of the scene and interviewing witnesses.

“Once we’ve completed that process we’ll be in a position to identify exactly what has occurred,” he told Sunrise on Monday.

“We’ve collected a significant amount of evidence from the scene. And we anticipate as we process that evidence and as we interview further witnesses we’ll get a clearer picture on exactly how it’s occurred.”

Paine also said road conditions are a “very significant factor in what happens on the roads” and will be investigated.

“As we respond to these incidents, we investigate them holistically to look at the different factors as to how and why it might have occurred,” he said.

The bus was carrying 33 people when it crashed with the caravan travelling in the opposite direction in a 100km/h zone.

It’s believed none of the people travelling in the four-wheel-drive were among those seriously injured.

Paine on Sunday acknowledged the “very significant impact and very significant consequences” of the crash, encouraging anyone not coping well with the trauma to access support.

The bus was heading to Townsville, about 90 minutes’ drive from where the crash took place.

The Bruce Highway was closed in both directions as emergency services responded.

- With AAP