A surfer survived a close encounter with a fin at a remote beach yesterday - but it wasn't the sort of fin you'd expect.

The man in his 20s was at a remote beach north of Whangamata when he sustained a large cut to his leg from the fin of a surfboard.

The Auckland Westpac Rescue Helicopter crew were dispatched at 1.22pm. When they located the beach the man was being treated by St John Ambulance paramedics.

The man was flown to Auckland City Hospital in a serious condition.