New Zealand has begun a clean-up effort to remove an oil slick created by a cargo ship that struck a reef off the country's North Island.

Oil recovery teams began scooping up oil that has leaked from the ship and salvage crews arrived Sunday to perform the sensitive task of pumping fuel from a crippled 47,000-ton vessel.

With weather conditions expected to deteriorate any day, maritime officials say removing the oil from the stricken vessel was the top priority.

The Liberian-flagged container ship Rena, loaded with 1,700 tons of heavy fuel, got stuck on a reef near New Zealand's Tauranga coast Wednesday. None of the 25 crew members was injured, but the ship's hull suffered damage and pumps had to be used to remove water from the cargo area.

The oil that has leaked out of the ship is a threat to dolphins, whales, seals and other maritime wildlife in the pristine Bay of Plenty. It has already killed some seabirds.

New Zealand health authorities on Sunday warned people not to eat seafood from the bay until further notice.

Prime Minister John Key is scheduled to visit the area later Sunday.