A crocodile farmer from Rockhampton in central Queensland says people should keep an eye out for saltwater crocs in floodwaters.

John Lever says the reptiles swim over land in search of food during big wets because their traditional feeding grounds are wiped out by freshwater floods.

He says crocodiles caught in a prolonged flood can become very hungry and can also find their way into popular swimming holes.

"I think this is where the real danger comes into play - there is a lot more danger after the waters recede," he said.

"You have land-locked crocodiles in waterholes, kids want to go play in them to keep cool and [have] never known of a crocodile there before and all of a sudden there is one in there."