SYDNEY (AFP) - A British backpacker missing for three days in Australia's harsh Outback was found safe and well on Friday following a major rescue operation, police said.

Mr Samuel Woodhead, 18, was last seen on Tuesday evening setting off from the Upshot Station homestead, about 130km from the far-flung central Queensland town of Longreach.

"He was found early this afternoon. He's been found safe and well, apart from suffering from a little bit of sunburn," a Queensland police spokesman told AFP.

"We understand he's in the process of being transported to Longreach Base Hospital," he said, adding that Mr Woodhead had no major injuries but was being taken to the clinic as a precaution.

Police said Mr Woodhead was found on Upshot Station, a property that sprawls across 1,300ha, but had no details on how he was found, and could not confirm reports that he became lost after going for a run.

"The assumption was made that he must have gone for a run," the spokesman said. "But he didn't tell anyone where he was going. That seems to have been the problem."

Australian authorities had held grave fears for the man's survival in a region where heat, a lack of water, venomous snakes and the possibility of injury could prove deadly.

Planes, motorbikes and four-wheel drives were being used in the search, with neighbours also combing the area on foot and horseback and an emergency services helicopter dispatched with medical staff.

"It's extremely harsh terrain in this area, and the isolation adds to the predicament," Inspector Mike Curtin said earlier on Friday.