A 62-year-old Oamaru man is in Dunedin Hospital after being shot in the head at close range.

The man was fishing with a friend on Tuesday night when he was struck by an air-powered bait launcher.

Police say the machine had malfunctioned and the two men were trying to get it going when it fired, shooting one in the head.

He was in a critical condition last night.

Police inquiries about the incident are continuing.

Bait launchers can cast bait attached to fishing lines about 300m using an air compressor.