TAURANGA, New Zealand - Rough weather has jostled a cargo ship stuck off New Zealand's coast and worsened its oil leak fivefold to make it the country's worst-ever maritime environmental disaster, the government said Tuesday.
Clumps of heavy oil from the Liberia-flagged Rena have washed up on pristine beaches near Tauranga on New Zealand's North Island, and environmental officials said 53 birds were found dead and 17 were getting emergency treatment to remove oil from their feathers.
"This event has come to a scale where it is New Zealand's most significant environmental maritime disaster," Environment Minister Nick Smith told reporters in Tauranga, adding that the clean-up would take weeks.
The ship has been foundering since it ran aground Oct. 5 on the Astrolabe Reef, about 14 miles (22 kilometers) from Tauranga Harbour, and the government has demanded to know why the ship crashed into the well-charted reef in calm weather. The ship owner has given no reason for the grounding, but says it is cooperating with authorities.
Rough weather in recent days has kept salvage crews away.
Late Monday, the 775-foot (236-meter) ship shifted significantly, spilling hundreds of tons of oil from an unidentified rupture in the hull, said Nick Bohm, a spokesman for Maritime New Zealand which is managing the emergency response.
Up to 390 tons (350 metric tons) of heavy fuel oil spilled from the hull Tuesday, a rate about five times worse than during the initial days of the spill, Smith said.
Bohm said a salvage crew had to be removed from the ship late Tuesday morning because ocean swells of 7-to-10 feet (2-to-3 meters) made conditions too dangerous. The swells were expected to increase as high as 16 feet (5 meters), he said.
Without the salvage crew aboard, oil cannot be pumped out of the ship.
"We're on standby at the moment and we'll see what's happening with the ship and they'll be redeployed as quickly as possible," Bohm said of the salvage crew.
"We're not saying it's going to break up yet; we're not convinced," he added, referring to the ship.
Divers are scheduled to inspect damage to the hull on Wednesday, Bohm said.
Maritime New Zealand said in a statement that a beach clean up began early Tuesday and that more teams would be deployed on Wednesday when oil is expected to reach the shore in greater quantities.
"A significant amount of oil is expected to come ashore in the next days," the statement said.
Rescue teams were also searching the shore for more wildlife affected by the oil.
Jen Riches, an official with WWF-New Zealand at Tauranga, said her environmental group is concerned over the fate of fur seals as well as birds such as the endangered New Zealand dotterel.
"If they don't manage to get that oil off and it ends up in the ocean, then that's going to be a disaster for marine wildlife, for people and for New Zealand," she said.
Marine crews began an operation Sunday to extract up to 1,900 tons (1,700 metric tons) of heavy fuel oil from the stricken ship the equivalent of about 10,700 barrels. But they had to halt the pumping Monday after managing to remove just 11 tons (10 metric tons).
In a statement, the owners of the ship, Greece-based Costamare Inc., said they were "cooperating fully with local authorities" and were making every effort to "control and minimize the environmental consequences of this incident." The company did not offer any explanation for the grounding.
The Rena was built in 1990 and was carrying 1,351 containers of goods when it ran aground, according to the owners.
In addition to the oil, authorities are also concerned about some potentially dangerous goods aboard, including four containers of ferrosilicon. Authorities said removing those goods was a priority.