Myrtle rust has been found at a second property in the Auckland region.
The plant disease attacks myrtle species, including pōhutukawa, ramarama and mānuka.
The disease was first discovered in Northland in May, and several cases have since been confirmed in Taranaki, Waikato and Bay of Plenty.
Last week a serious infection of several hundred ramarama plants was found on a commercial plant production property west of Auckland.
The Ministry for Primary Industries said a second infection had now been detected on ramarama plants at a home in the Auckland suburb of St Lukes.
It said a team was working to remove all affected plants to contain any risk of spread.