Boaties heading out on Otago waters this weekend are being asked to be vigilant of a pest fanworm

Recent pest surveillance found evidence of the Mediterranean fanworm at a wharf in Port Chalmers.

Environment Canterbury has also recently detected it at new sites in Lyttelton Harbour.

Otago Regional Council's Environmental Implementation Manager Libby Caldwell says they're urging all boat owners to report any sightings.

She says the long, pale brown worm should not be removed by the public.