Little Blue Penguins are among the many bird species being affected by oil from the wrecked cargo ship Rena.

It's at this time of the year Little Blue Penguins breed and this is being hampered by oil washing up on Tauranga shorelines.

The Little Blue Penguins breeding season has been impacted by the oil from the stranded ship Rena.

The number of breeding pairs in the Mount Maunganui area is around 200 to 300, with Maritime New Zealand's National Oiled Wildlife Recovery unit monitoring their burrows daily to help birds survive the oil.

WWF-New Zealand marine programme manager Rebecca Bird says if a penguin becomes oiled and tries to preen itself; it can swallow the oil and become very sick.

'Whilst these nocturnal penguins may not appreciate such close attention as they incubate their eggs, the monitoring is critical.

'The penguins come ashore during the evening to find their burrows, and many are becoming oiled crossing rocks covered in thick tar-like oil.”

Rebecca says if they find a bird that is heavily oiled, they will collect it and take it back to the wildlife recovery centre to be cleaned and rehabilitated.

'Around 120 little blue penguins have been rescued from the mount so far, and their chances of survival are comparatively good. Penguins are some of the most resilient birds in recovering from oil spills.”

Rebecca says they are facing a tough choice.

She says removing an oiled bird will give it a chance of survival, but its clutch is unlikely to survive.

'We checked on the pair of little blue penguins in the 'window nest' a couple of nights ago, and the mate was oiled so we had to take him away to the recovery centre to be looked after. Then the next night we found the other penguin was oiled and had to take her away.

'We hope that the birds we recover will be rehabilitated successfully, but it's heartbreaking to know that saving them means their clutch won't be reared.”

In an effort to save the clutch, the team placed the eggs with another pair of penguins, but Rebecca says the adoptive pair rejected the eggs.