LATEST: A large container ship has struck a reef off the coast of Tauranga this morning, with two cargo holds reportedly flooded.

Rena, a Liberia-flagged 235m vessel, was heading to Tauranga from Napier when it crashed in to the Astrolabe Reef, about 7km north of Motiti Island, around 2.20am.

A Maritime New Zealand spokesman said there were reports two cargo holds were flooded and the vessel was on a 12-degree lean.

The tanks containing the ship's heavy fuel oil were reportedly undamaged.

There was nothing to suggest there was a leak in the vessel at this stage, the spokesman said.

There were 25 people aboard the ship, and no reports of injuries have been received.

The Marine Pollution Response Service (MPRS) had been called and trained spill responders with equipment were heading to Tauranga this morning.

Members of the National Oiled Wildlife Response Team were also on their way.

Maritime NZ was working with the crew and had also activated its Maritime Incident Response Team, which was monitoring the situation from Wellington and had a safety inspector on board.

MPRS, with the Bay of Plenty Regional Council, was coordinating a flight over the area scheduled for around 8am to further assess whether the vessel was leaking.

It was low tide in Tauranga at 8am, with high tide at 2.30pm. The weather was fine, with light winds and the chance of some showers.

In August the Australian Maritime Safety Authority ordered the Rena detained for over a day.

The 32-year-old ship was found in Freemantle to have a number of serious deficiencies including defective hatchway cover, and incorrectly stowed cargo.

"Vessel has not been maintained between surveys," the Australian official report said.

It was allowed to sail as hatch covers were secured.