The captain of a badly listing ship stuck on a reef has been arrested, Maritime New Zealand (MNZ) said, adding that about 70 containers had fallen into the rough seas.
Oil from the vessel Rena has gushed into the environmentally sensitive Bay of Plenty and washed up onto beaches, where the containers were also likely to end up, MNZ said.
Wildlife has been found dead or contaminated.
The captain has been charged with operating a vessel in a manner causing unnecessary danger or risk and will appear in court on Wednesday morning over what the government has declared New Zealand’s worst maritime pollution disaster.
It was highly likely that more containers will come off the ship because of the severe weather conditions and the vessels heavy list, MNZ said, despite tying them down tightly to prevent them falling in.
“There are 1,368 containers on board. Eleven containers containing hazardous substances are still on the vessel and are not among the 70 estimated overboard,” an MNZ statement said, adding major shipping had been re-routed.
MNZ said an aerial survey, likely to go ahead later in the day when the weather improves, would give a clearer indication of exactly how many containers had toppled into the increasingly choppy waters.
The maritime body, which has issued an emergency telephone number for the public to call if they see any of the containers on the beaches, warned people they would be prosecuted if they tried to take what was inside them.
The Liberian-flagged Rena, which hit the reef 22km off the North Island coast last Wednesday, has leaked up to 300 tonnes of heavy fuel after being further damaged in a storm.
“I’d like to acknowledge this event has come to a stage where it is New Zealand’s most significant maritime environmental disaster,” Environment Minister Nick Smith told reporters at Tauranga on Tuesday.
Smith said there was little authorities could have done to prevent the disaster.
They have warned coastal residents to stay away from the viscous sludge, describing it as toxic, but many have ignored the advice and formed their own clean-up teams.
MNZ has said one of the Rena’s four fuel tanks had ruptured but was unable to say whether it was in the stern, where most of the oil is stored, or the largely empty tanks in the front, which has sustained the most damage.
Officials have warned that New Zealand faces a major disaster if the Rena breaks up on the reef and releases all 1,700 tonnes of oil on board, describing fuel offloading as the “top priority”.
Compared to some of the world’s worst oil spills, the Rena disaster remains small – the Exxon Valdez running aground in 1989 in Alaska dumped 37,000 tonnes of oil into Prince William Sound.
But it is significant due to the pristine nature of New Zealand’s Bay of Plenty, which teems with wildlife including whales, dolphins, penguins, seals and rare sea birds.