Queensland fruit fly larvae were found in fruit collected from two properties in Grey Lynn at the weekend, three weeks after the initial fly was caught.
The Ministry of Primary Industries (MPI) said four properties in the central Auckland suburb were receiving ground treatment for fruit fly.
The treatment involved laying insecticide pellets and spraying plants, and happened only at properties where adult fruit flies, larvae or pupae had been found.
The ministry thanked the residents of these properties for their ongoing support and said they were all in a close vicinity to each other.
MPI said no adult flies had been found over the weekend and the total number of fruit flies captured in Auckland remained at 14.
Officials said they were still confident they were dealing with a localised population that could be eradicated, but it could take several months.
DNA testing on all flies captured so far showed genetic similarity, which meant it was most likely a localised population.
The initial male Queensland fruit fly that caused the Grey Lynn operation to begin was found in a trap on February 16.
Since then MPI has restricted the movement of fresh fruit and vegetables in a controlled area around Grey Lynn and surrounding suburbs, and has also introduced tougher border restrictions in a bid to prevent further incursions.
Officials continue to work in the field setting up and checking traps to locate any further flies. Laboratory staff have been analysing hundreds of kilos of fruit daily to check for the presence of fruit fly larvae.
An established population of the Queensland fruit fly could devastate New Zealand's lucrative horticulture industry and result in restrictions on our international exports.
Badly bitten
*14 Queensland fruit flies have been found since February 16.
*Suburbs affected by the restrictions include Grey Lynn, parts of Western Springs, Mt Albert, Ponsonby and Kingsland.
*Four properties make up the centre of the outbreak.
*Eden Park is within the restriction zone and fans at cricket matches have not been allowed to take fruit or vegetables from the park.
*The Pasifika Festival this weekend has been shifted from Western Springs to Hayman Park in Manukau.