MAF Biosecurity says a foreign species of beetle that feeds on crops has been found in Auckland.
It says the hadda beetle, which is similar to a ladybird although yellow in colour, was reported by an entomologist.
The beetle is found throughout Asia and the Pacific region and feeds on the foliage of crops including potatoes, tomatoes and aubergines.
MAF Biosecurity response manager David Yard says a controlled spray programme has been carried out at Dove-Myer Park and the Auckland Domain where the beetles have been feeding.
MAF Biosecurity says a surveillance programme is also planned to determine the extent of the infestation, but there are no health concerns for the public.