The Department of Conservation says an unusual weather pattern is killing hundreds of seabirds.
It says the biggest La Nina pattern since 1975 is calming east coast waters, making it difficult for birds to find food.
A department vet, Kate McInnes, says tests show the birds are starving to death, and people should expect to see the bodies of birds such as penguins and gannets washing ashore for up to six weeks.
Dr McInnes says it is a sad but natural situation, and people should leave the birds to fend for themselves.
She says, however, that she is not concerned for the survival of seabird species because they had an active breeding season last summer.