They were all travelling on a Premier Motor Service coach which crashed down an embankment on the Bruce Highway about 5.30am (AEST).

The accident happened at Gibsons Creek, between Bloomsbury and Proserpine, about 1,000km north of Brisbane.

The bus driver, who was trapped after the accident, sustained head and spinal injuries as well as fractures to his arm and leg.

Three people were also taken to hospital in a serious condition with spinal injuries, a Queensland Ambulance Service (QAS) spokesman said.

Others injured in the accident had sustained fractures, lacerations and bruising, he said.

Premier Motor Service marketing manager Gordon Lowe said the injuries could have been much worse if the bus, travelling from Brisbane to Cairns, had not been fitted with seat belts.

"We've always been safety conscious," he said.

"All our coaches are equipped with seat belts."

Mr Lowe said the bus, carrying 23 passengers, was "almost brand new".

"The company has been going for about eight years and this is the first time we've had an incident like this," he said.

"Our safety record is second to none."

Mr Lowe said the company's "highly trained professional" bus drivers received regular breaks with four drivers during each Brisbane to Cairns service.

He said arrangements would be made to transport passengers who were able to continue travelling to Cairns on another service.

Six of the injured were taken to the Mackay Base Hospital, the remaining six were in the Proserpine Hospital.