Forest & Bird says urgent action is needed to avoid an environmental disaster and to minimise seabird deaths as a result of the oil spill off the Bay of Plenty coast.

Forest & Bird seabird advocate Karen Baird says many seabird species are particularly vulnerable because they are breeding.

Rena today, stuck, leaking, and on a lean.

'We need to ask why booms were not put around this ship yesterday to contain any release of oil,” says Karen.

'The sea conditions were good and containing the spill is much better than using toxic dispersants on kilometres of oil slick.”

The container ship Rena is spilling heavy fuel oil after becoming stuck on Astrolabe Reef, near Tauranga, at about 2.20am on Wednesday.

The Rena is carrying about 1500 tonnes of fuel oil and four seabird deaths have already been reported after fuel oil spilled from holes in the ship's hull.

'With no containment, we now need to keep seabirds off the oil slicks before they get contaminated.

'Having people go out in boats to keep the birds away from the oil slicks will save more birds and be better than waiting for the bodies, or distressed oiled birds to wash up onshore.”

The major risks will be to seabirds such as terns, gulls, gannets, penguins, petrels and shearwaters. They either dive into the water or land on its surface to feed.

'Landing in the oil slick is a death sentence for these birds.

'Their feathers will become clogged with oil and they can sink or drown, or be unable to fly.

'Swallowing even small amounts of oil can be fatal to them or their chicks when they try to feed them.”

Gannets have a large breeding colony on White Island and the fluttering shearwaters are currently sitting on eggs and feeding at sea in large flocks.

Diving petrel eggs are hatching and the adults will be feeding on krill and small fish to feed them.

Grey faced petrels are breeding on Mount Maunganui and islands in the area, and will be feeding in waters around the ship grounding, while white-faced storm petrels are feeding on plankton on the sea's surface as they prepare to lay their eggs.

Forest & Bird and other environmental and conservation organisations are mobilising volunteers to help deal with the effects of the oil spill.