Myrtle rust has spread to Taranaki.
Ministry for Primary Industries testing confirmed the infection at a plant nursery late this morning.
MPI's myrtle rust response controller David Yard says no plants will be moved and they're preparing to treat the area with fungicide.
He says they will also be inspecting the surrounding area in a 500m radius.
The infectious fungal disease, which puts native plants such as pohutukawa at risk, was discovered two weeks ago in the Far North.
It's believed to have been blown over from Australia.
Yard says the new infestation could signal the disease is here for good.
"As with Kerikeri, we'll be throwing everything at it to attempt to control it, but we are realistic that it is a huge challenge, given how readily the spores are spread by the wind."