Court action may be the next step for kiwifruit growers following confirmation the Psa strain that crippled the industry came from China.
Te Puke grower Rob Thode said University of Otago research just released was "absolutely huge" for the industry because it proved the Government was negligent in its border security.
He was now considering taking the matter to court.
Three university scientists investigated and compared the genetic make-up of Psa strains from Japan, Chile, China, Italy and New Zealand.
Associate Professor Russell Poulter said the core genomes (genetic material of an organism) of the four strains were almost identical. However, the genetic make-up of the New Zealand strains was a distinct clone.
"These findings paint a clear picture of an independent Chinese origin for both the Italian and the New Zealand outbreaks and suggest the Chilean strains also come from China," Mr Poulter said.
New Zealand Kiwifruit Growers' president Neil Trebilco said the research highlighted the importance of border security.
"What we don't want, of course, is for another variant of Psa in New Zealand. Having the one we've got is bad enough, but having another variant would compound the problems for us."
David Tanner, head of the Kiwifruit Vine Health/Zespri Psa research and development programme said the news further underlined how difficult Psa was to manage.
New Zealand First leader Winston Peters said High Court cases were bound to follow the announcement, estimating the damage already done to the kiwifruit industry at $900 million.
Ministry of Primary Industries spokesman Andrew Coleman said staff were watching the Otago research with interest and appreciated the work they were doing.
Three distinct mobile genetic elements, known as "integrative conjugative elements" (ICE), were identified in the research. These can affect or alter infectiousness and resistance to antibiotics.
The first was shared by the New Zealand strains and three strains from China. Another ICE was shared by Italian strains and a Chinese strain, while a third ICE was found in the Chilean strains.
Mr Poulter said some Psa could be more virulent due to the particular ICE it carried.
"This has worrying implications as strains of kiwifruit that are resistant to one type of Psa might not be resistant to another. This means strict border control by kiwifruit-producing countries is more important than ever," Mr Poulter said.
