Witnesses have said a rainforest zipline snapped before a South Australian man plunged to his death in Queensland’s far north.

The man, 50, was harnessed to his partner, 48, when they fell from the flying fox run by Jungle Surfing Canopy Tours at Cape Tribulation about 2pm on Tuesday.

American couple Samantha Salyer and Joseph Maghe said they had just finished the same section of the Daintree rainforest tour and saw the couple fall.

“We got to the fifth platform and there were two couples behind us,” they told the Seven Network. “There was a loud noise, we turned around, one of the lines had snapped and we saw them fall.

“It shook the entire tree we were on. They hung there, then they both came down at the same time.”

The man was pronounced dead at the scene, at Camelot Close, north of Cairns.

His partner was flown by rescue helicopter at 5.30pm to the Cairns hospital in a serious but stable condition.

She remained there on Wednesday with suspected pelvic injuries and injuries to her shoulder and arm.

Phoebe Kitto, a director of Jungle Surfing, offered her deepest sympathy to the families and friends of those affected by the accident.

“It will be thoroughly investigated by Workplace Health & Safety, which will receive our full cooperation,” she said.

“We are offering counselling to staff and to our patrons.”

The zipline takes people through the world renowned Daintree rainforest.

Police have secured the scene and said they would remain until two Workplace Health and Safety officers and an inspector arrived on Wednesday.

Detectives and Workplace Health and Safety will prepare reports for the coroner.

