Booms are being placed at Maketu and Little Waihi Beach today in anticipation of any fresh oil washing ashore from the wreck of Rena, Maritime New Zealand says.
The oil is forecast to reach the coastline east of Maketu tomorrow evening.
However, National On Scene Commander Alex van Wijngaarden said the oil would be much less than that which spilled in October, as the bulk of the oil has been removed.
"There are residual pockets of oil that they were unable to reach due to the extensive damage on the ship. However, we are talking tens of tonnes left on board - as opposed to the hundreds of tonnes we saw washing ashore in October."
Captain van Wijngaarden said the National Response Team was ready to deal with whatever quantities came ashore this time.
"We are regularly monitoring the oil on the water with aerial observation flights. The most recent one confirmed a stretch of sheen with some dark patches in it spreading about 500m from Rena. A lighter sheen, with no dark oil spots, stretches around 10km from the wreck."
Five containers and their contents have been removed from Waihi Beach and recovery teams are working to remove 10 more, in an area stretching from Bowentown to just north of Waihi Beach.
Plans are also being made to remove 11 containers from Matakana Island.
So far today there are no new reports of containers being washed ashore.
Vessel in its "death throes"
MNZ Salvage Unit Manager David Billington said this morning's observation flight showed that the two parts of Rena remain on the reef, with the stern section still about 75 percent submerged. A small amount of debris remains around the wreck, as well as a light oil sheen.
The stern, which has about 400 containers in its hold, is in a precarious position on the reef and was last night about 75 per cent submerged. As it sank it left behind tonnes of timber, debris and containers that littered Matakana Island and Waihi Beach.
Environment Minister Nick Smith said the Rena was "in its death throes" and the Government's priority was now minimising the environmental damage as it sank and broke up.
New Zealand Diving and Salvage general manager Howard Saunders says a technique known as saturation diving is likely to be used after the ship's stern began its descent yesterday, three months after grounding on the Astrolabe reef.
Mr Saunders said that by law the Rena would have to be removed after it sank the 80 to 90 metres to the seabed.
That would require one of the biggest and most dangerous salvage operations undertaken in New Zealand.
He said the salvors would probably be working in depths of greater than 30m, so they would have to use a saturation diving spread - rarely seen in New Zealand - with pressurised chambers and diving bells that enable divers to live and work safely at depth for days and even weeks.
One is in operation off the Taranaki coast at a natural gas rig.
"You can live down there with food ... sometimes they call them habitats and people live on the bottom, but most modern operations are not that long."
He said the underwater salvage job would be among the biggest projects in New Zealand's maritime history and possibly among the most expensive.
Some saturation dive teams charged US$150,000 dollars (nearly $190,000) a day.
"I think the Wahine took more than 12 months [to salvage] but that was done fairly slowly and the water depth was nowhere near as deep as it is here," he said.
Mr Saunders said removing containers from the Rena above water had been dangerous enough.
"Under the sea it's going to be even worse," he said. "If they are subject to any current or it's not stable on the bottom and it's moving around the whole operation becomes a bit of a nightmare."
Paul van't Hof, of Svitzer Salvage, would not be drawn yesterday on the future of the salvage operation.
"That's something we can only decide after doing our inspections, at the moment we would be guessing and we have to change our plans," he said.
The owner of the Rena, Costamare, has said in a statement the company and its insurers continue to fund the salvage operation, including the recovery of containers washed overboard.
"Following the further deterioration of the RENA on the Astrolabe Reef and sinking of the stern section, owners wish to assure all those affected, that the company continues to cooperate fully with Maritime New Zealand and other government departments to do everything possible to mitigate the effects of the situation."
More oiled penguins
Maritime New Zealand's national on-scene commander Alex Van Wijngaarden said oil spill response teams had placed booms in sensitive areas, and the oiled wildlife centre in Tauranga and volunteer programme had been reactivated.
Six penguins affected by oil from the Rena were reportedly being treated at the centre yesterday.
A spokeswoman for container recovery company Braemar Howells, Claudine Sharp, said it had identified 49 containers yesterday, of which about 25 had beached at either Matakana Island or Waihi Beach.
She said the company had 13 vessels between Waihi Beach and Motiti Island to try to catch the drifting containers and attach them to a specialised barge.
Yesterday more than 60 people were helping with the clean-up at Waihi Beach. At least 30 more worked from Papamoa to Kaituna Cut, and another 20 helped remove timber, paper, plastic and milk powder that continues to wash ashore from the Rena's cargo.
Transport Minister Gerry Brownlee yesterday praised the clean-up efforts of volunteers at Waihi Beach, saying they had "tolerantly put up with all the inconvenience that comes from these types of events".
Asked what the Government's position was on the wreck, he said it "will have to be removed".
Once the weather had settled, "a closer inspection will be able to give the technical experts a greater understanding of how the ship is likely to respond".