MOST oil has been removed from the stricken 3,300-TEU Rena, which had been grounded and spilling bunker off the coast of New Zealand's north island since October 5, and now efforts focus on removing 1,280 containers still onboard, reports Stuff, a Fairfax Media online publication.

Transport Minister Steven Joyce said removing the containers will take months. "The fragile state of the ship and precarious positioning of the containers aboard means this will be a long process," he said.

Athens-based Costamare, which owns the Panama-flagged MSC chartered Rena, has been told it must remove the vessel once work is complete. But fears remain that the vessel will split up, said Mr Joyce. There was a "strong possibility" that oil remained trapped aboard which could be released should the ship break up.

Maritime New Zealand (MNZ), the national coast guard agency, said the bulk of oil had been pumped from the vessel with less than 100 tonnes left.

"The sea water is pushing the oil up to the surface of the starboard tank. Now we have got to the last bits so they've got to allow that oil to rise to the top then they'll pump it off, then they'll have to wait a while until another bit rises to the top so they'll be slowly extracting that last bit. Effectively the bulk of it has been pumped," said MNZ.

More than 1,300 tonnes of oil from the ship which struck the Astrolabe Reef off the Tauranga coast. About 1,700 tonnes of bunker was on board. About 350 tonnes of oil spilled into the ocean.