Two more properties in Taranaki have tested positive for myrtle rust.

The discoveries at a nursery in Waitara and at a garden centre in downtown New Plymouth bring to five the known affected properties. A nursery and adjoining property in Kerikeri and another nursery in Waitara area also affected.

The infectious fungal disease, which threatens native plants such as pohutukawa, was discovered two weeks ago in the Far North.

"The new finds are disappointing but not unexpected," said Ministry of Primary Industries incident controller David Yard.


"The ministry expects to continue to find new locations of infection given the most likely scenario is that the fungal spores entered New Zealand from Australia during a major wind event."

At all the infected properties there are restrictions on the movement of plants or other risk materials off the sites.

They are being treated with fungicide, at-risk plants are being safely destroyed, and surveillance is under way in the areas surrounding the properties for signs of the disease.

Yard said growing conditions at plant nurseries were ideal for the fungus with many vulnerable young plants in sheltered, warm and damp environments.

"There has been a large amount of communication with the nursery industry and growers have been particularly vigilant in checking their plants."

MPI asks members of the public to report any suspected signs of myrtle rust to its Exotic Pest and Disease Hotline on 0800 80 99 66.

They advise people not to touch the rust or the plant, but to note the location and take photos of the symptoms and the plant.