Police and surf lifesavers gave up hope of finding the man at nightfall yesterday after three full days of comprehensive searches.

Mr Quinlivan had been sketching a seascape with his daughter about 11am when a freak wave hit the northern rock shelf on the beach.

Stefan Leonte had been walking on the rocks with a group of young people when the wave hit and sent him into the sea.

Mr Quinlivan dived in after Mr Leonte became caught in a rip and was carried 100m out to sea.

Mr Leonte was later discovered alive and well on a nearby beach.

Angus McIvor posted a tribute to Mr Quinlivan yesterday, saying he had worked for years in the Northern Territory.

"Both brave and an inspiration, Paul successfully recruited health professionals to staff a remote health centre east of Alice Springs," he said.

"His energy was tireless and he would think nothing of driving patients 330km to make an appointment in Alice.

"A staggering 95 per cent of indigenous patients made it to their appointments when he worked at the health centre. He made a great difference to all of us and will not be forgotten."