EXPOSED: A man sought by police after he was seen naked on Peka Peka beach.

Otaki police are trying to identify and track down a man photographed nude and in state of arousal on a Kapiti beach.

Sergeant Noel Bigwood said he was sent the photo a couple of days ago of a man with an erection on the beach between Te Hapua Rd beach access and Te Horo.

The photo was taken by local resident Brian Whitaker at 3.15pm on December 27, who was on the beach with his family.

Mr Whitaker rang the police but by the time Mr Bigwood got there the man had disappeared.

If police could track the man down they would consider laying charges, Mr Bigwood said.

"I was on the scene fairly quickly. I went straight to the hot zone, near the Te Hapua Rd entrance. Beachgoers said they had seen nude people, but not one in the state of arousal. A father with his family said he had told a nude guy he found it offensive and the man got a towel.

"If we can find the man it could be prosecutable, given there were young families around. If I was down there with my grandchildren and a guy came past standing proud, I would be upset.

"Expectations of behaviour at a Sunday school picnic are somewhat different to a public bar on a Friday night," Mr Bigwood said.

A group of local residents have been upset recently about nudity and nude men parading on the beach near Te Hapua Rd access.

Mr Bigwood is urging locals to contact the police immediately instead of sending letters of complaint to Kapiti Coast District Council, but which time anyone causing offence has gone.