Residents in Cambridge and Matamata are being asked to look for rooks and report sightings to Environment Waikato.
Rooks, which have been sighted in these areas, can pose a serious threat to farming as they feed on crops, damage pasture in search of grubs and tear open silage covers.
"EW wants to locate rooks around Cambridge and Matamata and control them before they can become more extensively established in the region," said biosecurity officer Brett Bailey.
Rooks are large, black birds, bigger than magpies, and are native to the UK and Europe. They come from the same family as crows and ravens, which are not found in New Zealand.
Living in both rural and urban areas, rooks nest high in the branches of tall trees such as gums and pines.
Environment Waikato employs professional contractors to control rooks.
"People should not try to control rooks themselves because this will cause them to scatter and spread further, making professional control more difficult," said Mr Bailey.
To report rook sightings or for more information about rooks and how to identify them go to www.ew.govt.nz/rook(external link) or phone 0800 Biosecurity.