Fears are today held for marine life at one of the Bay's favourite diving spots as it was revealed this morning more oil had leaked from the stricken ship in Tauranga's Harbour overnight.
Rob Service, who is in charge of the response, said a small amount of oil had leaked during last night's pumping operations on Rena, which ran aground off the coast yesterday.
Maritime New Zealand said they were not sure what kind of oil had leaked or how much, but had been assured it was a small amount.
Representatives of the salvage company were this morning on the vessel and had confirmed the leak had been stopped and only a small volume of oil had gone into the water.
Oil spill response equipment arrived in Tauranga overnight and was being deployed this morning.
"While reports of a leak are unfortunate, they are not unexpected. We were lucky in the sense that we had all of yesterday to get the team to Tauranga and get plans, equipment and people in place," Mr Service said.
The 236m vessel with 23 crew was well off course when it struck the Astrolabe Reef, six nautical miles north of Motiti Island, near high tide while en route from Napier to Tauranga about 2.20am.
The ship, which is three-quarters full with some 2100 containers and about 1700 tonnes of heavy fuel, has been at the centre of safety concerns in Australia including for cracked and rusted parts.
The vessel's hull was pierced in several places on the left side but the fuel tanks at the rear were not believed to have been damaged. Hydraulic oil could be seen on the surface of the water surrounding the rupture site yesterday afternoon.
Questions are being asked of how the ship came to hit the reef.
Russ Hawkins, of Fat Boy Charters, said the reef was like a "needle in a haystack".
You could go around there with no map and go up and down and all over and probably never find it."
Mr Hawkins said the reef was his favourite place to take people and overseas visitors were amazed at the marine life there.
"There's thousands of kahawai, and you have the schools of trevally ... I've seen a striped marlin there and at this time of year you can get the odd fur seal on the rocks," he said.
It remains unclear exactly what cargo Rena is carrying but it is understood there are some dangerous goods. Experts are trying to establish what they are and what risk they pose.
James Sygrove, communications manager for Maritime New Zealand, told the Bay of Plenty Times a salvage expert was coming from Singapore to assess the ship.
"Until this assessment has been carried out we are unable to comment on how long the salvage operation could last or what course of action will be taken to free the vessel," Mr Sygrove said.
The Marine Incident Response Team has brought in a team of trained spill responders as well as special equipment to the site.
The National Oiled Wildlife Response Team has also been called to Tauranga. Wildlife experts from Massey University are supporting the National Response Team and preparing contingency plans to manage any risk to wildlife.
Mr Sygrove said the deployment of the wildlife team was a precaution.
Dave Garnett, skipper and diving instructor at Earth 2 Ocean diving, said the reef was known as the "bait pond" because of its abundant marine life.
"There's always large schools [plus] a lot of big pelagic species like kahawai, your kingfish, your shark, mackerel, and the resident reef fish. It's one of the best dive spots in the Bay," he said.
Mr Garnett said the grounding of the ship was "a total screw-up" and it should not have been so close.
"I haven't seen ships close to Astrolabe Reef before. They should be out further," he said.
"If it's leaking on to this Astrolabe Reef, it's going to wreck it. If there's a swell, that's going to damage the reef and all the birds that hang around there."
Diver Tony Clithero, from Dive Zone Tauranga, agreed.
"There's a lot of sponges and stuff. There's heaps of fish life. Just your usual things: bronze whalers and seals, stuff like that, [plus] you've got all the birds," he said.
He said any spill, if not contained, "would put a good kill" on the marine life around the reef.
Brett Keller, of Tauranga Marine Charters, said the reef had a steep incline and was "really the only bloody thing you can hit" in that area of water.
"How the hell they managed it is obviously pretty pathetic," he said.
"If they are accurate in saying it's hydraulic oil, well that just floats on top. If it was fuel then that would be a major blow. Fuel oil is pretty close to crude, and that's messy."
Sunfish Charters' Gisela O'Neill said she was shocked.
The charters regularly go to the reef with clients.
"I think it's a worry. We don't dive too much but we do fish, it's definitely not good."
See today's Bay of Plenty Times for extensive coverage and more photos of the shipping incident.