Over a thousand birds had been found dead since MV Rena's reef crash resulting in oil spill almost two weeks ago, as operations in oil removal have been stopped because media vessels are getting too close to the ship.

"We cannot risk lifting or dropping off heavy equipment while these vessels are nearby," said a spokesman for Maritime New Zealand, referring to the sea vessels of media, approaching to get a closer look of the stricken MV Rena.

"Air operations cannot be undertaken while these vessels are in the area and have ceased while this is resolved," MNZ said further.

Meanwhile, 140 live birds have been found sick and were being treated in relation to the oil spill. There were also 36 rare dotterels in purpose-built aviaries.

This developed as the tanker Awanuia has been placed in position, ready to get oil from the Rena when pumping begins.

MNZ said it could not tell how long the oil-removal operation would take, as it would depend on the weather, the cargo ship's stability and the viscosity of the oil.

Noting that 1,346 tonnes of oil - down from 1673 tonnes - is believed to still be on board the vessel, MNZ warned that the operation "will be a long process" and weather-dependent.

Weather forecasts in the area are fair for today and tomorrow, although rain is forecasted later tomorrow, raising worries over sea swelling.

MNZ Salvage coordinator Bruce Anderson MV Rena was not as stable as initially thought on Astrolabe Reef, in which it got wedged in since October 5.

"While the bow is settled onto the reef and stuck firm, the stern is in a precarious position," Anderson said.

Clean up continues on New Zealand coastlines affected by the oil spill off Tauranga. Nearly 5,000 people had registered for the beach clean-up, as 382 Defence Force personnel were also actively assisting in the clean-up efforts.

Maritime NZ warned locals repeatedly that attempting to clean the beach without specialist knowledge could be harmful; hence briefings are conducted for volunteers.

Volunteerism comes alive in NZ as food such as barbecue and sausage rolls have been donated by a local bakery and a radio station while beverage refreshments also came in from a bank and other sponsors for the clean-up.