The Ministry for Primary Industries says about 180 staff are working on the response to an increasing number of fruit flies found in an Auckland suburb.
A male Queensland fruit fly was found in Grey Lynn on Monday, then another two adults, larvae, and pupa yesterday.
Restrictions on the movement of fruit in the area have been extended, and will now last up to two months.
The ministry said its people in the area were trapping and collecting fruit for examination in laboratories.
It was not been able to say whether any more fruit flies had been found today.
The restrictions in place in Grey Lynn after the fruit fly discoveries are being extended, and will now last for up to two months.
A third fly was found yesterday, which prompted the Ministry for Primary Industries to increase its response and widen the high-risk zone in the suburb of Grey Lynn.
The ministry's chief operations officer Andrew Coleman said he was confident limiting the movement of fruit and vegetables, and putting out bait for the flies would work.
He said the original plan was for the restrictions to last a couple of weeks, but since a third fly was found, the time-frame has been adjusted.
"It will take longer than the two weeks that we had first envisaged around this, it's likely to take up to a couple of months.
"But internationally and certainly in New Zealand it's our experience in the past is that these fruit flies will be eradicated."
Farmers market monitored
Biosecurity officials have been monitoring shoppers at the Grey Lynn farmers' market as a result of the restrictions in place due to the fruit fly discoveries.
People are banned from taking fruit and vegetables out of the high risk zone.
Posters and warning signs about the fruit fly are plastered throughout the small community hall where the market's set up.
The owner of the largest fruit and vegetable stall, George Vezich, said his business had taken a hit.
But the alternative was far worse, he said.
Several biosecurity and Ministry for Primary Industries staff walked around the market, handing out pamphlets and answering questions.
They said shoppers were mostly well informed about the threat.