The H5N1 virus first emerged in China in 1996 but new strains are now showing up in populations of wild birds and poultry in Africa, America and Europe.
Invercargill-based Department of Conservation kākāpō veterinary adviser Dr Lydia Uddstrom said the virus had yet to reach New Zealand but the threat was something that was "always up there on the things we’re thinking about".
"There’s been a new strain of avian influenza that’s spread far further than it has traditionally in the past.
"It has now spread to South America and it’s getting closer to New Zealand.
"So certainly it’s something that we are keeping a very close eye on.
"It’s something that MPI’s [Ministry of Primary Industry] also keeping a very close eye on."
The virus could arrive on poultry products, but Dr Uddstrom believed the most likely way would be via migratory birds such as godwits that are arriving in the country now.
"So migratory birds are kind of the most obvious route that it could ultimately arrive."
However, the risk to New Zealand was lower than for some northern hemisphere countries where migratory distances were less.
In September, the United Nations Food and Agriculture Organisation reported 250 virus outbreaks or events in animals in four geographic regions over the previous month.
Two human cases were reported.
In Arizona, 21 out of a world population of only a few hundred condor vultures have died from the HPAI strain detected there in April, and emergency use of a vaccine has been approved.
While many New Zealand birds, including kiwi, would be impacted by the virus, the low number of kākāpō would put the continuation of the species at risk.
"You always have that concern that there are so many fewer of them that to lose any would be a real blow," Dr Uddstrom.
Inoculating kākāpō with a vaccine widely used in the northern hemisphere would be an option if the virus reached New Zealand.
There are three breeding sites for kākāpō including two on islands in the South that are relatively secure from predators and biological threats.
Strict biosecurity measures for visitors to breeding sites were already in place.
"So in terms of the virus, it’s just a matter of waiting and watching closely."
Similar concerns arose in 2006 when The New Zealand Herald reported Doc had plans "under way" to vaccinate birds — kiwi and kākāpō among about 20 species considered to be at greatest risk.
The kākāpō’s lack of mating enthusiasm also counts against it.
None were expected to breed next year, for instance, because the forests where they live are unlikely to produce a good crop of the rimu tree seeds they feed on, Dr Uddstrom said.
