A German backpacker survived by eating flies after becoming stranded by floodwaters in Queensland's outback, police say.

Daniel Dudzisz, 26, was reported missing last month while on a walk between Windorah and Jundah, south-west of Longreach.

He was picked up by a motorist late yesterday afternoon near Cooper Creek at Windorah.

Police Inspector Mark Henderson says Mr Dudzisz had become lost and was stranded in the bush between two flooded sections of the Barcoo River for about 10 days.

"He did see the choppers looking for him but they couldn't see him due to the tree coverage," Inspector Henderson said.

Mr Dudzisz told officers he waded through floodwaters and ate flies to survive the ordeal.

"If you hadn't heard it with your own ears, not that I have but my officers have, they said they certainly wouldn't have believed it," he said.

"There is nowhere else he could have been.

"He joked about never going hungry in the Australian outback because of the amount of flies you can eat for their protein apparently.

"He had some baked beans and cereal when he left Windorah and exhausted that pretty quickly, and said he'd been eating flies ever since."

Inspector Henderson says Mr Dudzisz refused medical treatment at Windorah.

"He certainly was hungry, but other than that he was in reasonable spirits," he said.

Police said last month Mr Dudzisz had been walking for several months through New South Wales and Queensland but had been in regular contact with police.

However, aerial and ground searches over the last few weeks were launched when police had not heard from him when he left Windorah on February 17, where he was believed to be walking 90 kilometres to Jundah.

The extensive searches had failed to find him and authorities were concerned because Mr Dudzisz had limited food supplies and was an insulin-dependent diabetic.

When his family in Germany was contacted during the search operation last month, they said they were not concerned about his welfare, as Mr Dudzisz has been self-sufficient on similar trips in the past.

Inspector Henderson says Mr Dudzisz was regretful authorities had searched for him, but he remained determined to continue his walk through to the Northern Territory.

"He has made an agreement now that he will stick to the main roads now rather than going cross country," Inspector Henderson said.

"He understands the risks and is disappointed and regretful that we had been looking for him and caused people to be looking for him."

Residents of Windorah say they are relieved Mr Dudzisz has been found safe and well.

Many locals had volunteered their time in the search for the tourist.

Windorah shop owner Diane Geiger says Mr Dudzisz looks to be in good health.

"He looks fine - he didn't look any different to when he was in here the day he went missing on February 17," she said.

"He didn't look terrible - he still looks in good health.

"He still had a big smile on his face and he looked all right to me."

Marilyn Simpson, from the Windorah pub, says Mr Dudzisz is "quite a private person".

"He was a little overwhelmed with the fuss that was happening when he did turn up," she said.

"He went directly to the shops, stocked up on some food, and then he went down to where he stayed when he was last here, which was a little picnic area in a park here and had his food that he bought."