Maritime New Zealand says despite many reports of dead birds coming in, not all have been affected by oil from the broken container ship Rena.
The ship has been grounded on Astrolabe Reef, off the coast of Tauranga, since 5 October last year, spilling oil and container debris.
The authority says penguins have a naturally high mortality rate at this time of year which could be why a lot of dead birds are being seen.[image:4410:half:right]
A manager of the team looking after wildlife affected by oil, Teri McClelland, says little blue penguins are in their moult period.
"There's a reasonably long moult season, between December and March. The timing is actually quite good this year, as it means a lot of them are safely tucked away and not going into the water and coming into contact with oil or debris."
The oiled wildlife team had been conducting day and night patrols and had found very few penguins affected by oil.
The penguins have no waterproofing while the moult is under way, so they remain in their burrows and do not go into the sea to feed.
Ms McClelland says only small amounts of oil are reaching the shoreline and the number of birds being found that have been affected by oil are small.
Meanwhile, salvors have lifted a further 13 containers off the bow section of the Rena on Friday.