The stretch of highway where a horror bus crash killed three women and left others fighting for their lives has been condemned as an unsafe “goat track”.

Two men remain in a critical condition after Sunday’s crash between a Greyhound bus carrying 33 people and a 4WD towing a caravan near Gumlu, in the Whitsundays region on Sunday.

The vehicles were travelling in opposite directions when they collided in a 100km/h zone on the Bruce Highway just after 11am. The bus was heading to Townsville, about a further 90 minutes’ drive away.

Paramedics assessed 27 people at the scene following the crash.

Seven people were transferred to Townsville University Hospital.

Acting chief medical officer Jason Yates said three had been discharged by Sunday night.

Four people remained in hospital – two men aged 24 and 23 in critical condition and two more men, 27 and 51, in a stable condition.

Yates said the hospital had mobilised to respond to a mass casualty event.

“Our teams worked really hard. We were able to mobilise additional medical, surgical, nursing, allied health and social work staff, who all came in on a long weekend to do their thing,” he said.

Police described the chaotic crash scene as “very, very confronting” as investigations continue into the cause of the tragedy.

The Bruce Highway was closed at Gumlu for about 12 hours in the aftermath of the crash.

On Monday, Whitsunday Mayor Ry Collins said the stretch of highway could be challenging and felt like a “country road”.

“The challenge is this is the national highway … For many of our southern listeners, if you are to drive the road it doesn’t feel like a highway, it feels like a country road,” Collins told ABC radio.

“There’s no shoulders on the road, it is a fairly open section. So I’d imagine the vehicles coming either way would have been able to see each other but there’s obviously been something happened here where one’s veered into the other’s lane.”

Local MP Dale Last said the head-on crash occurred on a section of highway that was “breaking up”.

“It’s full of potholes. It’s not a very safe section of highway at all,” the LNP MP said.

“It is nothing more than a goat track. That’s what the locals call it.”

Queensland Police Superintendent Graeme Paine said on Monday the crash occurred on “open highway”.

Road conditions certainly form a major part of the investigation,” he said.

“An incident of this nature is very complex, so we want to go through that holistic investigation before we really move towards looking at exactly why and how it’s occurred.

“The impact that had occurred, it pushed the bus across to the railway line – hence we had the closure of the railway line at the time.”

Queensland Premier Steven Miles said he was “shocked and saddened” by news of the crash.

“Our thoughts are with their loved ones and those impacted by this tragedy. Queenslanders are sending you strength,” he posted on social media.

Greyhound Australia said in a statement the company was “heartbroken” about the fatal crash.

“This is a tragic incident. Our deepest sympathies go out to those involved and their families and friends,” they said.

The company is working with police as the investigation into the cause of the accident continues.

The Bruce Highway has since reopened. Queensland Rail is to inspect the railway line before deciding if it can reopen.

-with AAP