Salvors trying to pump fuel off the stricken ship Rena have been forced to put off their operation until tomorrow because of the weather conditions.
Andrew Berry, Maritime New Zealand's salvage unit manager, said salvors battled away this morning in winds over 30 knotts and swells between two to four metres.
He said the barge Awanuia was no longer able to remain safely attached to the rear of the Rena.
"She let go of her mooring lines and also the fuel transfer line, the salvors remained aboard until the early hours of this morning and when another set of salvors were put aboard the decision was made to secure the ship to close the manhole cover into the fuel tank, close the watertight doors and then to leave the ship," said Mr Berry.
"The salvors have advised their intention to board again tomorrow morning when conditions have hopefully abated."
Salvors have not connected a booster pump, which could improve the rate at which oil comes from the ship although Mr Berry could not confirm how much faster the transfer rate would be once it was connected.
He said Rena's forward section remained firmly pinned to Astrolabe Reef but the stern section was moving backwards to some degree with the waves and change of tide.
The crack in the ship's starboard was being monitored but with the present weather conditions on its side it was taking a battering from the swell.
Mr Berry said a white oil sheen with smaller amounts of darker oil in it had spilled from the Rena this morning.
"It's coming from the Rena and is moving out to see with the prevailing wind and is naturally breaking up thanks to the wave within two to three kilometres of the ship."
Transport minister Steven Joyce said the ship was precariously placed with the rear of the ship balanced on the edge of the reef.
"Obviously that means it's important that we maintain the safety of the guys who are on there, we don't want anybody losing their life through this exercise."
"So I think we're in a little bit of a wait and see game to see what happens to the ship over that period and then hopefully if it gets through that period okay then we will see a resumption of pumping of oil from the ship."
Earlier today, Prime Minister John Key said the next day a "critical" period for the Rena recovery.
He said it was crucial the wreck stayed intact so more oil could be pumped off in calmer weather tomorrow.
Meanwhile, Mr Joyce called a $1 million donation from the company that leased the Rena "a start"
Mediterranean Shipping Company's this afternoon pledged the $1 million to help with the disaster's clean-up, but say the "voluntary donation" is not being paid out of moral obligation.
Its managing director Kevin Clarke told media this afternoon that the company owners "genuinely feel the suffering" happening in Bay of Plenty in the wake of the disaster.
Mr Joyce said the company did have a moral obligation to the clean up effort and may be called on again in future.
"I wouldn't necessarily accept that that's where it ends."
Mr Clarke emphasised that the company did not own the Rena, did not employ its crew and were not responsible for the Rena's maintenance and operation.
"At our meeting with the Minister of Transport, Steven Joyce, yesterday we discussed other ways in which we might support the cleaning operation. Today we thus want to put at the disposal of the relevant authorities $1 million as a voluntary donation."
The company has said it is not legally liable to pick up the tab for the clean up, which has cost $4 million so far.
Asked whether the donation was a sign the company felt moral obligation, Mr Clarke said: "I look at this as a kind offering by the owner of MSC."
Mr Clarke was forced to back-track after saying the company had also noted "what's tantamount to a fairly slow response".
When asked to explain the comment, Mr Clarke said there was a feeling in the community that the clean-up was slow to commence but admitted he had not visited any the beaches yet.
Phil Abraham, general manager of MSC New Zealand, said the company was not pressured into donating.
"There's no guilt at all expressed by ourselves. We do feel for the people of Bay of Plenty. We felt a corporate responsibility to help," he said.