The Northern Territory Amateur Fishermen's Association says people who wakeboard in crocodile-infested waters are "complete idiots" and could ruin some of the best fishing spots in the Top End.

ABC local radio in Darwin has received pictures of people wakeboarding at Corroboree Billabong on the Mary River, south of Darwin.

Association spokesman Chris Makepeace says it is lucky no one has been killed.

He says he hopes there are no new restrictions put on the billabong.

"I just hope we have not got somebody who is going to run around and say we have got to do this and we have got to do that because somebody is stupid enough to go and wakeboard on a billabong," he said.

"I mean, you spend time on Corroboree, I spend time on Corroboree and I would not dip my toe in there, with the size of the crocodiles and the number of them."

Mr Makepeace says new laws will not solve the problem.

"Who could think that it would be necessary to make a law to make people stop wakeboarding on Corroboree?" he asked.

"You don't need to have laws for that.

"If people want to be stupid, they will be stupid.

"(It) doesn't matter what the law is, people will be stupid.

"End of story."