The regional council in Bay of Plenty is conceding defeat in its battle to eradicate the invasive Argentine ant.
The council will now only become directly involved in control operations to protect sites of high value biodiversity.
The council said a great deal of money has been spent on surveillance and control operations, but it remains highly likely that new arrivals of Argentine ants will come in from neighbouring regions where control is not being undertaken.
There are 28 known sites of ant infestation in Tauranga, Mount Maunganui, Rotorua and Whakatane.
Argentine ants, which have multiple queens and create giant colonies, can be identified by their multiple trails and their tendency to march over objects placed across their path.
They are also known to be great hitch-hikers, establishing nests in potted plants, compost heaps and rubbish bins.
