An Australian man dubbed "Crocodile Dumb-dee" for trying to ride a huge crocodile after a drinking spree Wednesday described how he just wanted to play with the animal.

Michael Newman, 36, said he climbed into the enclosure of Fatso, a five-metre saltwater croc who lives at a wildlife park in Broome in northwestern Australia, to pat him and sit on his back.

"I thought, 'Well, I will jump the fence and go from behind its tail and pat it and sit on its back,' " Newman told public broadcaster ABC.

"And within like one split second before I even slightly touched its back, it already had me by the leg," he said.

Media reports said Newman tried to drip beer into the mouths of two female crocodiles before moving onto the giant Fatso.

He said he shouted at Fatso to let him go before escaping from the pen and returning to a nearby pub with severe leg injuries, where he drank a beer while waiting for an ambulance.