58 field workers are in the area checking surveillance lure traps and collecting produce for inspection.

"No further Tau flies have been found," says the Ministry's Manager Surveillance and Incursion Investigation, Brendan Gould. "We are focused on finding out if there is a population of these flies in the area. If one exists, we want to get rid of them as they pose a threat to some horticultural crops."

MPI has a Controlled Area in place extending 1.5km from the location of the fly find. There are 81 traps in the A Zone, a circular area extending 200m around where the fly was found, and 166 traps in the wider B Zone which extends out to 1,500m from the find.

"Our traps are very efficient. If there are further flies present, these traps will find them," Gould says.

While MPI works to rule out the presence of any population, residents in the Controlled Area are asked to ensure restricted fruits and vegetables (see below) are not moved from their property, other than into disposal bins provided. There are 135 disposal bins conveniently located throughout the area.

Tau flies like to feed on pumpkins, melons, cucumbers, capsicum, zucchini, beans, mangoes, eggplant, papaya and passionfruit.

MPI asks the public to not move this produce from the Controlled Area, unless it’s been purchased from an MPI-approved store. Approved retailers will seal the produce in a plastic bag for safe transportation. To date there is 1 approved retailer – the Countdown Manurewa at 227 Browns Road. MPI keeps an up-to-date list of approved retailers on its website.

"We appreciate that restrictions can be inconvenient but public support is vital to success and we've always had terrific community buy-in," Gould says.

Over the past few days MPI staff have contacted all retailers in the Controlled Area that sell fresh produce and informed them about the movement restrictions. The Ministry has also contacted local schools, pre-schools and churches.

"We will be working closely with schools, as the new school year begins, to make sure parents have good information about what can and can’t go into school lunchboxes."

Those who think they might have seen a Tau fly in their area are asked to call the Ministry for Primary Industries' hotline on 0800 80 99 66.