Two jet skiers who pulled up next to a five-metre-long shark for a closer look came off second best when it turned on them off Fraser Island in southern Queensland.

Libby Williams was riding on the jet ski with another person when they slowed down to track the shark in shallow waters near the island's Ungowa Creek.

The shark, which an expert said was a great white, was swimming away from them before it turned and bit the jetski, narrowly missing Ms Williams' leg.

"I literally had to move my leg so it didn't get mauled," she said in her Facebook post, which included video of the incident that had been viewed more than 160,00 times since Sunday.

"Notice the lack of screams?

"I think I must have been too scared.

"I was ready to head home after that!"

No-one was injured in the attack although the jet ski did have some small scuff marks.

Bond University shark expert Daryl McPhee was confident the shark was a great white, which are known to frequent the waters around Fraser Island.

"They are not always aggressive, but just like a lot of people, I guess it thought the jet ski was annoying," he said.

"I don't think it thought they were lunch.

"I think it was the shark being annoyed and it telling the source of annoyance to go away."

Fraser Island is an "important residence" for the great white, alongside Lakes Entrance in Victoria and the Port Stephens area in New South Wales, Dr McPhee said.

They are listed as a vulnerable species, with females growing up to six metres.