No more Queensland fruit flies have been found since a single male was discovered in a surveillance trap in Whangarei near the Town Basin almost a week ago.
The first checks of traps set last week have detected no more insects. However, it is still too early to rule out a colony somewhere and the Ministry for Primary Industries is maintaining its trapping programme.
The insect, which infests more than 100 species of fruit and vegetables, is one of the biggest threats to New Zealand's $4 billion fruit and vegetable export industry.
Ministry spokesperson Andrew Coleman said it takes about two weeks without another specimen being found before an all-clear can be given.
More than 70 ministry staff inspected gardens and rubbish bins on Monday for any signs of the insect and collected and re-set traps.
Results from a second set of traps, set up in an area known as Zone B, were due to be released on Monday but this has been pushed back until on Tuesday night.
Meanwhile, residents in the control zone up to 1.5km from where the male was found need to remain vigilant.