The plant disease myrtle rust has been found at a fourth location in Northland through customer tracing from the original infected nursery.
The new find was on a plant in a private garden in Kerikeri.
David Yard, who is in charge of the Ministry for Primary Industries' myrtle rust response, said the infected plant was one of two bought by the property owner at Kerikeri Plant Production, where the disease was first detected in early May.
The plants had been removed and destroyed and the property sprayed with fungicide. The surrounding area was also inspected for signs of the distinctive fungus, which causes bright yellow spores to erupt from young leaves.
Kerikeri Plant Production has since reopened but can't sell plants from the myrtle family - including pohutukawa, manuka, feijoa and eucalypts - until further notice.
MPI has praised the owners for detecting the rust early and alerting MPI immediately.
The other Northland finds were on a ramarama tree in a property next door to the nursery and in a garden in Taheke.
Meanwhile the number of infected properties in Taranaki is climbing almost daily and now stands at 33. There it has been found in seedlings and mature trees in plant nurseries, private gardens, an orchard and a golf course. An infected pohutukawa hedge has been cut down and destroyed.
The affected species so far are pohutukawa, ramarama, eucalyptus, manuka and lilly pilly. It has not been found yet in feijoa. The disease could devastate some native species and threatens the manuka honey and feijoa industries.
If you see what could be signs of the disease, don't touch the plant but note its location, take a photo and call 0800 80 99 66. Go to www.mpi.govt.nz/myrtlerust for more information.