Scientists are warning that native trees including the pohutakawa, rata and manuka are at peril as a devastating fungal disease moves closer to New Zealand.
Department of Conservation staff on Raoul Island one thousand kilometres to the northeast of Northland have confirmed the discovery of myrtle rust on pohutakawa trees there.
The Director of New Zealand's Biological Heritage National Science Challenge, Andrea Byrom, told Morning Report the fungas is a bright yellow colour and looks like "pustules" or powder on the leaves of trees.
She says it can kill trees and spreads very easily via spores.
"As soon as the pustules on the leaves erupt they release the spores and they can travel very long distances on the wind. So, yes, there is a real risk that it will reach our shores eventually."
She says the fungus is very difficult to spot and urges New Zealanders on the mainland to be vigilant.
Dr Byrom says a team of scientists are studying the fungus.
"We've got time to prepare and we've also got time to do the studies to better understand the impact of this fungus on New Zealand native plants."