The Department of Conservation has a new target in its sights, but rather than rats and possums, it is trying to eradicate an invading species of butterfly.
The department says the Great White Butterfly poses a huge threat to vegetable crops like cabbage, cauliflower and broccoli along with native cresses.
DOC says the butterflies are twice the size of the small white butterflies commonly seen in gardens.
It says the butterfly has only been spotted in Nelson so far and it wants to wipe it out there before it has a chance to spread.
The department is asking members of the public to report sightings of the butterflies along with their caterpillars and eggs.