Animal protection authorities are pulling "bagfuls of dead birds" from Auckland's waterways as the warm, sticky summer compounds the spread of a toxin outbreak.

Hundreds of dead or sick birds suffering from paralysing disease botulism have been found by officials or handed in to animal shelters.

In one case, the SPCA has spent days pulling several species of dead and dying fowl from a disused quarry in South Auckland.

Auckland SPCA inspector Vicki Border said the current outbreak of avian botulism was the worst she had observed in Auckland.