20 tonnes of oil has escaped from a ship which struck a reef off the coast of Tauranga.
The MV Rena struck the Astrolabe Reef some 20 kilometres from the city's Port early on Wednesday morning, sparking a scramble to coordinate a salvage and cleanup operation.
Maritime New Zealand says an observation flight has confirmed the oil appears to have stopped flowing from the ship and the slick is now predominantly sheen, or very thinly spread oil.
Response Manager Rob Service said the oil sheen is moving away from the nearby islands, and spreading westerly about two to five miles from the ship.
"There are darker patches in isolated pockets but they seem to be assisted by yesterday's wind," Mr Service said.
"Obviously from our perspective this is good - we will be continuing to monitor the slick. The observation flights are vital for directing our response, and we are doing these every few hours."
Four vessels from the New Zealand Defence Force have been deployed for the response, comprising Rotoiti, Taupo, Manawanui and Endeavour.
An Iroquois helicopter arrives today and around 500 defence force personnel are on standby for a shoreline cleanup if needed.
Maritime Pollution Response national coordinator Mick Courtnell told a media conference at the Ports of Tauranga he was hoping to get people training in the harbour this afternoon.
Mr Courtnell said there were about 40 people including some who helped with the Gulf of Mexico disaster.
He said they would have the best equipment available.
"By tomorrow we will have the ability to clean up 540 tonnes of oil," he said. "By Monday, we will be able to accommodate more oil than what is out there."
He said there were efforts underway to sort out a way of disposing of the oil. "It doesn't just go down the drain."
Courtnell said about 20 tonnes of oil had escaped the ship - a fraction of the potential 2000 tonnes aboard.
Tomorrow, the team would start getting oil off the surface using two boats with a large floating skirt between them.
At the Te Maunga wildlife centre for birds severely covered in oil, director and vet Brett Gartrell said the team were caring for five little blue penguins and two shags.
He said there was room for up to 200 birds with 14 teams of three people out on the water and along shorelines looking for wildlife caught by the spill.
"They are dehydrated, they have started to see the toxic effects of the oil and starting to get anaemic and very cold."
At the centre, the birds are stablised, given fluids, food and warmth for a day before they were strong enough to be cleaned of oil. He said the birds had yet to be completely cleaned of oil.
"We have to lift this heavy fuel oil out with a lighter oil. We're using canola oil and we're massaging that into the feathers then washing them in buckets of water with detergent."
The water was warmed to the birds' body temperature of 41 degrees.
"Some of them are only lasting a few minutes and we have had to stop because they are so weak."
Gartrell said the philosophy of the response was not to simply treat endangered species. "We're saying human beings did this. We're going to put it right."
He also said many affected birds would have died and sunk quickly, weighed down by the oil.