A massive search effort is underway for an abalone fisherman still missing after 15 others were rescued on the first day of the abalone season in Western Australia.

A spokesman for Surf Life Saving WA says it is believed the 21-year-old Malaysian man was swept off rocks while fishing with with four other men at Yanchep Lagoon, 60 kilometres north of Perth, earlier on Sunday.

The four other men were also swept into the water but were later rescued.

Surf lifesavers say they have rescued a total of 15 people off Yanchep and Mullaloo beaches after the abalone season opened over the weekend.

The police air wing and divers are now involved in the search for the missing 21-year-old but bad weather continues to hamper rescue efforts.

WA's Emergency Services Minister Troy Buswell has called for fishers to remain vigilant.

"Our coastline is very dangerous in Western Australia, the sea is very unpredictable and people need to be extremely cautious," he said.

"The sad reality is a number of people are lost at sea on an annual basis in our state."

Abalone fishing is permitted for one hour on the first Sunday of each month until March.