Five trucks and two ambulances crash on Bruce Highway south of ...

Low visibility from fog and smoke have contributed to a "chaotic" multi-vehicle crash on the Bruce Highway, about five hours' drive north of Brisbane. 

The highway has remained closed since the crash, which happened south of Miriam Vale at Gindoran about 2am Tuesday.

Queensland Ambulance Service Director of Clinical Operations Tony Hucker said the crash, which involved a number of B-Double trucks, stretched across one kilometre.

Three people were trapped and had to be cut out of trucks. (Supplied)

Two paramedic units travelling to the scene were then involved in a crash.

Both paramedics received minor injuries but were able to continue to manage the scene and treat patients before being assessed at hospital later in the morning.

"Not only is that distressing, but it held them up getting to the patients they really wanted to care for," Mr Hucker said.

"But to their credit, they soldiered on, they got their gear out of their ambulances, threw their gear into a fire truck and travelled about a kilometre to the accident scene."

Tony Hucker described the crash scene as chaotic. (ABC News: Josh Dye)

Mr Hucker said a line of about 30 trucks had pulled up behind the accident on what was a "really foggy, foggy night".

The Queensland Fire Department also confirmed a fire was burning near the Bruce Highway at Miriam Vale. 

A truck sustained serious damage in the Bruce Highway crash. (Supplied)

A man in his 20s with critical head and leg injuries was taken to Gladstone Hospital.

He was expected to be transferred to a major trauma centre in Brisbane on Tuesday.

A second man in his 50s was also taken to Gladstone Hospital with serious head, hip and leg injuries.

A man in his 20s with head, chest and leg injuries was taken to Bundaberg Hospital, while another two patients were assessed at the scene but declined transport.

Eight fire and rescue crews attended the crash, using cutting equipment to free the three men from the vehicles.

Tow-truck driver Corey Hindley said he had to swerve quickly to avoid being caught up in the accident and said visibility was low.

He said the ambulances crashed into a reversing truck trying to get off the road.

Three men were taken to hospital with serious injuries. (Supplied: Queensland Ambulance Service)

"The B-double's tried to get off the road and one ambulance has followed the other one and they've both hit the truck, then pushed them straight into the ditch," Mr Hindley said.

"I probably had five metres before I just saw the hazard lights of the truck and they're half on the road as well, coming around the bend.

"I've been in this game for 30-something years and I've seen it all.

"But you just didn't expect it, just a dead stop like that with no warning."

With the crash happening at the start of Road Safety Week, Mr Hucker said reminders were there everyday to take care on the road.

"You must drive to conditions," he said.

"Whenever you are driving at night the risk goes up and when you put fog into the mix it is dangerous, so you need to slow right down and if it's too bad, pull over and not drive at all.

"We need to be mindful that even on a good day, highway driving in this country is dangerous."

Steven Miles says the government will continue to invest in the Bruce Highway. (ABC News)

Premier Steven Miles was asked about the state of the Bruce Highway, and said his thoughts were with everyone impacted by the crash.

"This incident reminds us that our paramedics and indeed all of our first responders, they go to work every single day and they take personal risks to take care of us," he said.

He said there was $6 billion worth of projects on the Bruce Highway.

"We recently announced that we'd increase our annual contribution from $200 million to $250 million," Mr Miles said.

"We'll continue to invest and upgrade the Bruce each and every year because it's the most important road in our country."

Police expect the Bruce Highway to remain closed for most of the day.

Diversions are in place from Gin Gin, via Mulgrave Street into Bundaberg Gin Gin Road, Rosedale Road, Lowmead Road, Tableland Road through Fingerboard Road to Miriam Vale. 

Drivers are urged to drive to conditions, detour not suitable for heavy vehicles.