The number of wild animals reported killed in an oil spill from a cargo ship that hit a New Zealand reef more than three months ago is just a tiny fraction of the real figure, a major conservation group said Friday.

With the 45 dead oiled birds reported by New Zealand shipping authorities since the Liberian-flagged Rena began to sink on Saturday, the total recorded number of animals killed in the disaster stood at 2,066, according to WWF-New Zealand.

"The true number of wildlife killed by the spill will be far greater than the numbers recovered - the corpses the teams are collecting are the tip of the iceberg, and of course the number of animals affected by the spill is greater still," said WWF-New Zealand marine program manager Rebecca Bird.

"This latest release of oil occurred during a significant storm, so oiled birds would have drowned more quickly and many will disappear from view," said Bird in a statement.

"The vessel breaking up, discharging more oil and harming more wildlife, clearly puts more pressure on an already damaged environment. However if this had happened before the majority of the oil was removed, it would have been an even greater catastrophe," she said.

WWF praised the wildlife recovery efforts led by the National Oiled Wildlife Recovery Team coordinated by Maritime New Zealand ( MNZ) as "world class."

However, WWF-New Zealand marine advocate Bob Zuur said, proposed legislation governing New Zealand's offshore environment - the Exclusive Economic Zone and Continental Shelf (Environmental Effects) Bill - would fail to protect wildlife from future spills.

"It appears that its primary purpose is to smooth the way for the government's Petroleum Action Plan, which aims attract more oil and gas exploration in our oceans," Zuur said in the statement.

"It will allow petroleum development in areas which are so significant for wildlife they should be never be exploited."

WWF was calling on the government to protect areas important for wildlife, and strengthen the legislation, which was open to public submissions until Jan. 27, to reduce the risk of spills.

The call came as MNZ warned more oil would wash up on beaches, but said recent rough seas, which had stopped salvage operations, had also broken down much of the latest spill.

"It is likely we will see fresh oil reaching shorelines at some point, but it is likely to be in small quantities. We are ready to deal with whatever comes ashore," said MNZ national on-scene commander Rob Service in an MNZ statement.

MNZ salvage unit manager David Billington said Friday that salvors had acted quickly to secure a container holding 660 bags almost 17 tonnes of plastic beads that had come ashore.

The beads posed a threat to wildlife, which might ingest them, but MNZ had received no reports yet of wildlife affected by the debris from the wreck, said Billington in the MNZ statement.

Two senior officers from the ship's Filipino crew are facing charges in connection with the Rena's grounding on Astrolabe Reef, about 12 nautical miles off the east of the North Island, on Oct. 5 and the resulting pollution.