An unusual school-holiday activity is on offer for children in Nelson this week.
As part of its intensive campaign to rid the region of the great white butterfly, the Department of Conservation is offering a $10 reward to anyone who manages to catch one.
The pest is threatening native cresses and could pose a significant threat to the country's agricultural sector if allowed to spread.
So far, nine great white butterflies have been handed in, and several dozen smaller white butterflies.
Conservation Minister Nick Smith says it is a great opportunity to involve school children in conservation, as well as helping them earn some extra pocket money.