Four people are recovering after a dramatic water rescue in Porirua Harbour this morning.

Police said they were alerted to the emergency about 11am.

They were told a small boat had capsized and four people were in the water, a police spokesperson said in a statement.

"One was clinging to the boat's semi-submerged hull about 200 metres from shore. Three other people attempted to swim to shore, but ended up holding onto rocks about 50m from the coastline.


"A police officer entered the water together with members of the public to assist those on the rocks and bring them safely to shore."

The Coastguard then arrived and two police officers entered the water and retrieved an exhausted man still clinging to the boat, the spokesperson said.

Ambulance staff helped those rescued, who were suffering from hypothermia and had swallowed sea water. Three were taken to Wellington Hospital for observation.

The Westpac Rescue Helicopter also attended the rescue.

Police were pleased everyone was safe, but noted lifejackets, while being available, were not being worn, the spokesperson said.

"With winter just behind us and the water becoming more attractive for recreation, now is a good time to remind all boaties of the importance to always wear a lifejacket."