A second Facialis fruit fly has been found in South Auckland, less than 100 metres from the first one.
Biosecurity says the single male fly was caught in a trap in the Otara controlled zone.
Spokesperson Catherine Duthie says it shows their processes are working.
That brings to four the number of fruit flies found in Auckland in recent weeks.
The department says it's highly unlikely a breeding population will establish here because of our climate.