No further Queensland fruit flies have been found since the potentially devastating pest was detected in Whangarei this week.
A single fruit fly was found in a routine surveillance trap in the Parihaka area on Tuesday, only 400 metres from where another fly was discovered in January.
The Ministry for Primary Industries believes the latest discovery is unrelated to the previous find.
It has stepped up trapping and monitoring in the area, with about 60 staff working in the field today.
No more fruit flies have been detected, the ministry said.
A 1.5km controlled area, with restrictions on the movement of fresh fruit and vegetables, remains in place.