Numerous sharks have been spotted in waters along Victoria's Surf Coast in recent weeks.

Fairhaven beach was closed for a second day on Saturday as three helicopters patrolled the state's southwest coast for the possibility of more sharks.

Authorities said two Westpac rescue helicopters will continue patrolling the coastline over the summer with the help of the CFA's Firebird 300 helicopter.

Fisheries Victoria said more sharks have been spotted this year than in previous years, particularly during the Christmas and New Year period.

More than 30 sharks were seen along the Victorian coastline on Boxing Day alone.

"We are asking Victorians to keep up to date with the reported shark sightings and take heed of warnings," Fisheries Victoria director Travis Dowling said on Saturday.

The majority of the sharks spotted have been bronze whaler sharks, but a few white sharks have also been spotted by fisheries observers.

If swimmers and beach-goers see shark-spotting helicopters hovering above the water and sounding a siren, they should leave the water immediately until the shark has passed or until further notice from surf patrols.