The same pancake-sized blobs of oil that have blotted the Western Bay of Plenty coastline were found at White Island yesterday and are expected to arrive at East Cape by Saturday.
Last night, the crippled 47,000 tonne container ship was threatening to break apart on the reef amid a fresh bout of bad weather bringing swells up to 2.5m high.
The poor weather forced salvors to cease the pumping of oil from the vessel at 11pm last night, however three staff remained on board.
MetService forecaster Sarah Garlick said there has been some heavy rain - but the biggest concern for the response team will be the swell.
"It's about two metres at the moment and we're expecting that to ease back later this afternoon and into the evening to about one metre," she said.
Ms Garlick said the swell combined with an onshore wind will be causing some problems for the teams.
Meanwhile, the Government painted a bleak picture of a long response to the Rena clean-up and a potential bill to the taxpayer of millions of dollars.
It is yet to commit to a possible financial package for affected businesses and workers in the Bay of Plenty, almost two weeks after the Rena struck the reef.
Maritime New Zealand salvage unit manager Bruce Anderson said there was some oil not contained in the vessel's fuel tanks which was expected to have spilled last night.
Much more could spew out if the Rena was dislodged.
"If the vessel falls off the reef it could puncture a tank," Mr Anderson said.
"You don't know what's going to happen if it falls off the reef."
One tank at the stern of the Rena contains about 700 tonnes of oil and a tank at the rear starboard side contains another 300 tonnes.
Salvors have ramped up their pumping efforts, so far sucking about 70 tonnes of the Marmite-like oil 150m through a 7.5cm hose into the bunker barge Awanuia.
Drew Shannon of Switzer Salvage said the priority was to discharge the fuel without damage to the environment but staff were also working feverishly on a plan to remove the containers and eventually the vessel itself.
Transport Minister Steven Joyce said he did not rate the chances of salvors finishing the job before the ship broke apart.
The prow of the Rena is settled on the reef, but its rear was hanging over by about 60m.
Weather conditions, bringing showers and northerly winds today, were not expected to ease until the weekend.
Weatherwatch.co.nz analyst Philip Duncan said while the Rena was likely to be pelted by brisk northwesterly winds of up to 50km/h and northerly swells of about 2.5m, it was unlikely to face the punishing 4m waves which damaged it last week.
"The winds will pick up again possibly on Wednesday, but should ease back at the weekend ... if we can get through the next couple of days, then there's a good window of weather."
Meanwhile, Mr Joyce yesterday met the managers of the Mediterranean Shipping Company, which chartered the Rena, about the company's "moral obligation to assist".
"They have given me an undertaking that they will be looking to provide assistance in both cash and non-cash terms," Mr Joyce said.
The ship's owner, Costamare, is responsible for covering the salvage operation, and is thought to be legally liable for up to $12.1 million of the cost of the clean-up under the Maritime Transport Act.
But Mr Joyce admitted more oil leaking was inevitable, and the final bill for the clean-up could be in the tens of millions of dollars.
"There are too many variables at this point, basically around how much of that oil comes off the ship, when and in what way."
The clean-up bill so far is estimated at $4 million.
- Derek Cheng, James Ihaka and Jamie Morton
