Another Queensland fruitfly has been found in the Auckland suburb of Northcote, bringing the total number to eight over the past three and a half months.
Biosecurity New Zealand is stepping up efforts in the suburb and will begin placing bait on fruit trees to attract and kill adult flies, especially females, Biosecurity NZ said in a statement.
The current restrictions on the movement of fruit and vegetables remain in place, and trapping and collection of fallen fruit in some of the controlled areas will continue, Biosecurity NZ spokesperson Dr Catherine Duthie said.
"While it is concerning there has been another detection, it still doesn't tell us that there is a breeding population.
"What it does is raises the potential that Queensland fruit flies remain in the area, albeit at very low levels.
"Our teams on the ground will continue removing fallen fruit from backyards in the A-zone, and placing bait on fruit trees.
"The baits are toxic to fruit flies ... we have taken every precaution to make sure the baits are safe around people and animals."
Biosecurity NZ will give people living in the area at least 24 hours' notice before placing bait in their property and will provide them with detailed information about the programme.
The latest find means an expansion of the B Zone in Northcote, and the establishment of a new A Zone with a radius of 200m around the new detection.
The controlled area of 1.5km will be expanded west from the latest detection.
Biosecurity NZ are asking residents in the A Zone to avoid composting fruits and vegetables.
For disposing of fruit and vegetable waste, they are encouraged to use a sink waste disposal unit if possible, or the bins provided by Biosecurity NZ.
These bins will be delivered shortly and residents advised of their location.
For the B Zone – no fruit and vegetables grown in the Zone can be moved out of the controlled area. Produce that has been sourced commercially from outside the area can be moved.
"We know it's a huge inconvenience but it's vital for our horticultural industries that we do this," Dr Duthie said.
"We don't want this pest to establish here."