The 47,230-tonne Liberian-flagged Rena, grounded for three months on Astrolabe Reef, finally broke in two about 22 km off Tauranga on the east coast of New Zealand on Sunday after being pounded by waves of up to 6 metres (20 feet).

Maritime authorities and salvage crews have tried to remove fuel oil and containers from the ship, which ran aground in calm conditions on Oct 5. But fuel and cargo continued to leak in rough seas, causing New Zealand's worst environmental disaster in decades.

At least five containers had washed ashore at Waihi Beach, a popular spot for holiday makers, Maritime New Zealand spokesman Bruce Fraser said.

"There are a lot of containers and debris in the water and washing up on the beaches," he said. An oil sheen was spreading 3kms (1.8 miles) from the stricken vessel and small amounts of oil was washing up on nearby islands and beaches, he added.

Timber, plastic and dozens of sacks of milk powder also littered the beach after an estimated 200-300 containers stacked in the 236-metre (775-foot) ship were washed into the sea when it broke apart.

Police said they had closed Waihi Beach to the public after reports of people removing items that had washed up.

"The expert advice we have received is for people not to approach items washed ashore for health reasons and we appeal to those people who have taken objects to return them to the beach where they can be managed by decontamination crews," Sergeant Dave Litton of Waihi Police said.

More than 20 containers were filled with cryolite, a toxic chemical, while others held everything from meat to household goods and cases of wine. Some have been tagged with transponders and the Navy was scanning the area with sonar to ensure nearby commercial operations at the Port of Tauranga POT.NZ could continue, Fraser said.

Salvage teams have pumped more than 1,000 tonnes of oil out of the ship over the past three months, though some remained onboard.

Thousands of birds were killed by the earlier spill and it has taken months to clean up the shore. Half a dozen penguins were picked up overnight, some of them covered in oil, Maritime NZ said.

Braemar Howells, a marine salvage firm, estimated that up to 300 containers of the some 830 left on the Rena were lost overboard when the ship broke in half.

About 390 containers had been safely removed earlier.

The Rena's captain and navigation officer, both Philippine nationals, have been charged with operating a vessel in a dangerous manner, and releasing toxic substances, which carries a maximum fine of NZ$300,000, or two years in prison.

They are due to appear in court again next month.

The vessel is owned by Daina Shipping, a unit of Greece's Costamare Inc. (CMRE.N) and was under charter to Mediterranean Shipping.

(Reporting by Lincoln Feast; Editing by Ed Lane)

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