Debris from grounded ship washes up on New Zealand beach

(CNN) -- Debris from a cargo ship that ran aground off the coast of New Zealand last year, and split in two over the weekend, washed up on a local beach Monday.

Four shipping containers also came ashore on Waihi Beach, and another seven are within a mile of the shore, Maritime New Zealand said in a statement. Police closed public access to the beach.

People are being encouraged to steer clear of the water, and to report whatever debris they see. So far, the reported debris includes timber, milk powder and plastic material.

"There is inevitably going to be a lot of mess and disturbance for the next few days while this is cleaned up and we would like people to use common sense and stay well away from the debris -- in some cases this will mean staying out of the water as well as away from material washed up on the beach," National On Scene Commander Alex van Wijngaarden said in the statement.

The Rena, a Liberian-flagged vessel, struck the Astrolabe Reef, about 12 nautical miles off the city of Tauranga, on the North Island, in October. It split in two over the weekend, triggering fears of a fresh oil spill.

Hundreds of tonnes of oil have already leaked from the ship, leading New Zealand's environment minister to call the spill the country's most significant maritime environmental disaster.

But on Monday, maritime officials said there is "no indication of a significant release of oil from the Rena, although a sheen of oil is still visible off the vessel."

Between 200 and 300 containers on the ship were lost overboard when it broke in two, Maritime New Zealand said.