Myrtle rust is a fungal disease that is found on plants such as pohutukawa and manuka.

A fungal threat to native plants has been found in Auckland for the first time, and there are fears it could spread rapidly throughout the region.

Myrtle rust has been found on several hundred ramarama plants at a commercial plant production property in the Waimauku area of West Auckland.

The Ministry for Primary Industries was notified earlier this week of the possibility of the infection, which officers from MPI have since confirmed.

Bob Francis confirmed his business Francis Fresh Ltd was the one affected.

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It had been closed down for now and he was being as helpful as possible with MPI, he said.

"There's heaps of people going around with white suits on just checking every speck, that sort of thing.

"We will know more in a couple of days."

Francis Fresh did not distribute many plants it grew locally, he said.

"We do pittosporums and different foliage, one of them is Lophomyrtus, and they are for export, mainly export."

Myrtle rust can cause significant damage to plants such as pōhutukawa, mānuka, kanuka and rāta and can kill mature trees.

No country has successfully eradicated the disease.

Myrtle rust spores are microscopic and can easily be spread across large distances by wind, or via insects, birds, people or machinery.

Myrtle rust response controller Dr Catherine Duthie said controls were put in place in an attempt to prevent further spread of the disease.

"This is a significant, new find given the new location and the extent of the infection," said Duthie.

"However, sadly, it is also an expected detection. While myrtle rust has been relatively dormant over the winter months we have been expecting new infections to be identified as we head into the warmer summer months and the fungus begins to release spores again."

Forest and Bird Auckland's Nick Beveridge said he was shocked to hear it and he hoped the outbreak could be contained.

"It's really bad news for Auckland."

Waimauku was not far away from a large regional park, he said.

"Just on the top of the kauri dieback issue in the Waitākere Ranges Regional Park. It's just what we don't need. It'd be a double whammy."

The ranges was covered in plants that could be affected, particularly kanuka, rata and around the coast, pohutukawa.

"That would be a huge blow if it got in there," he said.

According to the MPI website, myrtle rust can kill infected plants and can have long-term impacts on regeneration of young plants and seedlings.

The first outbreak of the disease occurred in Northland in early May and it has since spread to Taranaki, Te Puke and Waikato.

This is the first time the disease has been found in Auckland.

* If you think you might have found myrtle rust, MPI asks you don't touch it but take a photo and call 0800 80 99 66.