An investigation is under way into the spread of Psa-V to the south Waikato but it looks likely the kiwifruit vine-killing disease was introduced by human error.
Kiwifruit Vine Health chief executive Barry O'Neil said Te Awamutu was an unusual place to find the disease.
The closest affected orchards were in Waihi and South Auckland so it was unlikely to have spread naturally, he said.
"If it was a windborne spread, we would have thought it would have been closer to those areas. It's against the prevailing wind," Mr O'Neil told the Bay of Plenty Times.
He said the spread of the disease was likely to be because of the movement of risk items such as plant cuttings, roots or contaminated machinery, or equipment brought onto the orchards.
The two Waikato orchards that have returned positive test results for Psa-V were prudent about their hygiene so it has not yet been established where the disease came from, Mr O'Neil said.
As well as looking into where the disease came from, the group is investigating other orchards it could have spread to.
Mr O'Neil is hopeful that with fast work, they will be able to minimise the spread of Psa-V as kiwifruit orchards in the Waikato are more spread out and predominantly grow the green variety.
Continued below.Related Content
Cyclone Donna: North Island in firing line as ex-cyclone merges
Auckland man charged with arson over Piha fires
Barter Barber Sam Dowdall: Cutting hair, talking about suicide
A 12km containment area has been set up around the affected Waikato properties and the 26 growers in the region are monitoring their vines closely.
There are about 90 orchards in the Waikato that produce 3-4 per cent of the country's kiwifruit.
Psa-V was first discovered in the gold kiwifruit variety grown in Te Puke in November 2010. The disease has since spread to other areas and now affects all varieties.
"There's no such thing as a resistant variety so all varieties will be affected.
"Some will be more affected than others," Mr O'Neil said.