The person responsible for vandalising traps on Brow Peak near Arrowtown last week does not understand New Zealand's pest problem, Predator Free Arrowtown co-ordinator Ben Teele says.
A volunteer checking the trapline along the hill's ridge on Saturday found more than 20 of the traps either blocked with stones or kicked over.
Mr Teele said the traps were among 35 laid in a circle between Brow Peak and Sawpit Gully, near Arrowtown, in January.
They had already proven their worth, catching ferrets at the highest altitude recorded in New Zealand.
He could only speculate on the vandal's ''thought process''.