A $300 reward is being offered for sightings that lead to the capture of a bird threatening New Zealand's native birds, and fruit and vegetable crops.
The Department of Conservation (DOC) believes there are at least five red-vented bulbuls in Auckland, which it says are one of the most invasive bird species on earth.
DOC is offering the reward to anyone who provides information that leads to the capture of one of the birds.
"These prolific breeders have been found in Auckland twice before and successfully eradicated. They're back and we need to act fast to ensure they don't have time to make themselves at home,'' spokeswoman Liz Brooks said.
The payout will go to the person who provides the first sighting that directly leads to a successful capture.