The Ministry for Primary Industries says it's taking all necessary steps after the discovery of a Tau Fly yesterday.

The single male fly from South Asia was found in the Auckland suburb of Manurewa.

Manager of MPI's surveillance and incursion investigation Brendan Gould says MPI is monitoring the situation.

"We've put in place controls of vegetables in and around the area where we found it in our surveillance trap, and we will be increasing our surveillance effort there to try and find if there are any more flies around."

He said those living in the controlled area will be provided with further information, but the public can help to prevent the spread of the Tau Fly.

"Ideally they shouldn't be taking any of the target's vegetables out of those controlled zones."

Gould said the public can also help by keeping an eye out, and should ring MPI on 0800 80 99 66 if they see anything unusual.

Meanwhile, Horticulture New Zealand's waiting until mid-next week to find out if the fruit fly's going to become an issue for exporters.

MPI chief executive Mike Chapman says unless another fly is found when traps are emptied mid next week, it shouldn't be a threat.

"What we need to establish and what MPI's doing is they're putting out more traps around the area where it was found and this is to establish if there's more than one of them."

Mike Chapman said the fly is not considered to be as economically threatening to New Zealand horticulture as the Queensland fruit fly.