In his Nature File column in last Monday’s Otago Daily Times, Anthony Harris, of Otago Museum, asked readers if they had noticed growths on waxeyes.
Afterwards he received nine accounts from the public of what was "unmistakably" bird pox, or Avipoxvirus, he said.
The correspondence was from Lawrence, Mosgiel, parts of Dunedin and Waitati, and seemed to show a "severe outbreak".
The disease causes pustules, blood sacs and diphtheria-like symptoms and can affect the lungs, resulting in the death of the birds.
Eventually it would disappear from the population, although it could spread to other bird species, Mr Harris said.It was "quite concerning".
"There’s not really much you can do about it.
"My advice for people is to just keep on feeding them as they normally do. If they stopped that the affected birds would go elsewhere, fly further away and spread the disease."
If not contained it could spread more widely through New Zealand, he said.
Belleknowes resident Dave Wilson said he was in his garden recdently and noticed "something was wrong" with a pair of waxeyes.
"I went to get my camera and looked at it on the screen and saw that something was odd."
He had fed the birds for a while, but it was the first time he had ever seen the waxeyes with such growths, he said.
"There were two birds together and both had it, which was interesting, too. They’re forever squabbling and getting quite close."
Associate Prof Bruce Robertson, of the University of Otago’s zoology department, said the disease was fairly common among birds.
He had also seen it in sparrows and finches and it could possibly already be in populations of endemic birds.
He had not noticed an outbreak this year, although it could just be in population pockets.
"In some instances it can be really bad and result in the death of the bird. I imagine it could spread, especially around bird feeders and those kind of places."
It seemed it was mostly the more unhealthy birds which were affected by the disease.
It could be found in other parts of the country, he said.The Department of Conservation was unable to comment yesterday.
