Genetic scientists from the University of Otago are looking at China as a likely origin for the kiwifruit vine killing disease PSA.
PSA has infected nearly a third of the country's kiwifruit orchards, most of them in the Te Puke area.
The research shows genetic similarities between the bacterial strain found in New Zealand and one discovered in China.
Associate professor Russell Poulter says the PSA strain in China has characteristics of a "close relative" to the type in New Zealand.
"The evidence seems pretty clear that (PSA) got from China into both Italy and New Zealand."
The study was commissioned by two of New Zealand's largest kiwifruit growers - Seeka and Eastpac.
Seeka chief executive Michael Franks says it is a glaring omission that Ministry of Agriculture and Forestry (MAF) officials did not speak to the University of Otago when they produced a report on 5 December tracing the disease.
MAF deputy director general Paul Stocks says it had already identified China as a possible source of PSA, along with Italy and Chile.
He said the department didn't receive the Otago University research until Christmas Eve, after it had produced its report, but will incorporate it when the report is updated in the New Year.
Mr Stocks says it is possible the bacteria was transported to New Zealand via imported pollen, a practice which was stopped immediately after the outbreak was discovered.