A third Queensland fruit fly has now been found in Auckland.
Like the others, it was found in the suburb of Grey Lynn. Primary Industries Minister Nathan Guy said it was a male.
"We've just found out that we've found one Queensland fruit fly male in a trap, it's a shame, there are 140 people that are working on this response."
Mr Guy said they were going to ensure that there was 100 percent dog detector screening at international airports.
This followed a second fly that was found this morning along with 39 larvae and one pupa in Grey Lynn. Officials said the female had not mated.
The Ministry for Primary Industries said a resident found the second insect in a lemon tree on his property, trapped it and reported it.
It was found in the part of the control area called Zone A, which was labelled high risk by the Ministry.
The first fruit fly was found on Monday.
Ministry for Primary Industries Chief Operations Officer Andrew Coleman said thanks must go to the resident who captured and reported the second fruit fly, allowing MPI to act swiftly to scope the problem.
"Our investigators immediately visited the property concerned where they found lemons and plums containing Queensland fruit fly larvae," Mr Coleman said.
"In total, at close of operations last night, MPI confirmed that one fly, 39 larvae and one pupa had been found at the property."
"We have every confidence that treatment will quickly and effectively eradicate this population. We have successfully eradicated previous incursions of fruit fly - notably the Mediterranean fruit fly in Auckland in 1996."
Mr Coleman said initial treatment would involve placing bait in fruiting trees to attract and kill female fruit flies. The bait would be applied high up in trees and plants, away from children or pets.
"A second line of treatment will involve some targeted ground spraying of areas under fruiting trees where positive finds have been made.
"This involves using an insecticide that is safe for use in residential areas and has been proven to do no harm to people or animals such as family pets or livestock.
"No use of aerial spraying will be required," Mr Coleman said.
He added existing controls on fruit and vegetable movements remained largely unchanged except that the high risk Zone A within the overall control area has been slightly enlarged.
A ban on the movement of fresh fruit and vegetables (except for leafy vegetables and root vegetables) outside the control zone remained in place.