New Zealand's precious native myrtle plants including pōhutukawa, rātā, mānuka, kānuka and ramarama are vulnerable to the disease.
The fungus, which is mainly spread by wind, generally infects shoots, buds, and young leaves of myrtle plants.
Infected plants show typical symptoms including bright yellow powdery spots on the underside of leaves but can also show other symptoms such as grey powdery spots during the cooler months.
DoC's project manager for myrtle rust, Dr Fiona Thomson, says the website is an excellent tool for the public to learn what myrtle plants look like, how to spot myrtle rust and what to do when you find infected plants.
"The more eyes looking out for myrtle rust, the better we can monitor this disease and protect our precious myrtles," says Fiona.
* If you think you see symptoms of myrtle rust, especially in areas where it has not yet been found, remember to not touch the plant or collect samples, but take pictures and report it to Biosecurity New Zealand's Exotic Pest and Disease Hotline on: 0800 80 99 66 or visit www.myrtlerust.org.nz for more information.