A highly infectious fungal disease has been spotted in the Waitākere Ranges for the first time, infecting critically threatened native trees.
Myrtle rust is carried by the wind but until now hasn't been found in the Waitākere Ranges.
It infects trees including New Zealand's iconic pōhutukawa, mānuka and rātā, and can prove deadly to the plants.
The myrtle rust found in Waitākere Ranges has infected the ramarama trees, which are considered nationally critically threatened.
Auckland Councillor Richard Hills says the discovery of myrtle rust in the Waitākere Ranges was a matter of when, not if.
"Despite the inevitability, this will be distressing for many of our communities who are concerned that our native taonga could be affected," he says.
Myrtle rust was first found in New Zealand in 2017.
If people think they've seen myrtle rust on a plant, they're asked to take a photo of the infected leaves and a close-up of the spores and submit them to the iNaturalist website, where experts can confirm the infection.
People shouldn't touch the plant or come into close contact where they may accidentally transfer the spores to their clothing or gear, Auckland Council says.