More than 10 tonnes of fruit has been destroyed to prevent the spread of fruit flies in Auckland.

So far, eight fruit flies of two different species have been found in Devonport, Northcote and Otara since February 14.

Stu Hutchings, chairman of the Fruit Fly Council - an industry-led group - said the fruit fly findings were of great concern to fruit and vegetable growers.

But despite new findings in Northcote and Otara this week, there was no evidence of a breeding population.

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That should give fruit and vegetable growers confidence in New Zealand's biosecurity system and the response so far, Hutchings said.

Controlled Area Notices have been issued for the three affected suburbs, which means movement of fruit and vegetables in and out of these zones is restricted.

Fruit was also being collected for examination and in some cases, disposal.

"More than 10,000kg of fruit has been collected in the bins placed in the three affected response regions and disposed of," Hutchings said.

"Additionally, a significant amount of fruit - around 800kg - has been gathered from properties within the A zones for each of the three responses and examined for larvae, without any findings.

"All the flies have been found in traps, which are very sensitive and an internationally proven method of surveillance," he said.

"If there is a breeding population present, there is a high likelihood of finding it as the response continues over the coming days."

The first fly to be detected was a single male Queensland fruit fly in Devonport on February 14. Four more have since been found in traps in Northcote.

Three single male facialis fruit flies have been found in traps in Otara.

If either of the species became established in New Zealand, officials said it would have serious consequences for New Zealand's horticultural industry.