A "remarkably lucky" Australian man who forced a crocodile off his head by prising open its jaws with his bare hands has managed to escape with minor injuries, paramedics said.

The 44-year-old Queensland man fought off the creature while swimming at Lake Placid, near Cairns, on Thursday.

He had puncture wounds on each side of his face but was "very, very calm" when healthcare workers arrived to treat him.

"A crocodile had bitten his head, and in his effort to remove the jaws of the crocodile he put his hands in to try and prise the jaws apart," paramedic Paul Sweeney told reporters in Cairns. "In the process of trying to remove his hands, the jaws snapped shut on his forefinger. He's a remarkably lucky gentleman."

"Just a few centimetres lower and we have major blood vessels ... had one of those been punctured then it would have been a very different story," Sweeney said.

He added that the unnamed man estimated the saltwater crocodile was between a metre and a half and two metres in length.

Sweeney said the man had been swimming in that area three times a week for about eight years. "Certainly not a place I'd choose to swim," Sweeney said, describing him as a "very fit individual" and saying "his vital signs were remarkably calm when you consider the ordeal he'd been through."

"I would not be surprised if he ventured into those waters again for further exercise," Sweeney added.

The Queensland Environment Department sent a team to the site and said a "search for the crocodile responsible for the attack is now underway."

"Once rangers are at the site, any crocodile found to be present will be targeted for removal," they said.

Crocodile attacks in Australia are rare, but Queensland officials run a public safety campaign to alert residents to the risks of swimming or relaxing near croc-infested waters.

In 2019, a Queensland fisherman narrowly escaped an attack by poking a crocodile in the eye. And last year, a massive 14-foot crocodile was captured at a tourist spot in neighbouring Northern Territory.