Myrtle rust has been detected on the West Coast for the first time, on a young pohutukawa tree in Greymouth.
Doc warned last year that the disease had spread from the North Island into Tasman.
Myrtle rust attacks myrtle species, including pohutukawa, manuka, kanuka and rata.
Pohutukawa are not native to the West Coast, but the fear is for the other species.
The Ministry of Primary Industries said the find was made by a commercial property owner in Greymouth.
Doc said last year it was "seed-banking" plants that might be affected on the West Coast, in case the disease made it there.
"Anyone who finds it shouldn't touch it," a Doc spokeswoman said at the time.
Myrtle rust was first found at a nursery in Kerikeri in Northland in May 2017, and has since spread to Auckland, Te Puke, Waikato, Taranaki, Wellington, Tasman and now the West Coast.
As the fungus is wind-borne, it is expected to spread further. Any suspected cases can be reported to the biosecurity hotline: 0800 80-99-66.
