The dolphin watching charter boat that took on water with nearly 40 people on board had a hole in its hull, a crewman says.

A number of children were among passengers on board the MV Dream Weaver when it started taking on water in Tiri Channel, near Whangaparaoa yesterday afternoon, police said.

The Coastguard was notified about 1.48pm and responded with several vessels, including the police launch Deodar, which rescued 36 passengers.

Crewman Michael Clarke said assessors were yet to examine the boat.


"We were in heavy seas and the vessel just started taking on water and when we got it back onto dry dock it was obvious there was a breach in the skin of the vessel and that is why water was being taken in.''

The base was partitioned off at certain sectors so it was isolated to one area, Mr Clarke said.

"At this stage we're still waiting for assessment to come back to give us an idea of what actually caused the accident - it looks like we may have hit something first or something like that, but we're not too sure.''

He would not comment further until the assessors had been in touch.

Nobody was injured during yesterday's incident, but police reported some passengers were suffering from sea sickness.

Inspector Ian Booker of police northern communications yesterday said the vessel was an 18 metre power catamaran with a capacity of 60 people. However, the vessel was "nowhere near capacity'' at the time of the incident.

Maritime New Zealand had been advised of the incident.