There's speculation the kiwifruit vine killing disease Psa could have got into New Zealand because of a failure at the border.
An independent report commissioned by the Ministry for Primary Industries (MPI) following an outbreak of the virus in the Bay of Plenty failed to reveal how Psa got to New Zealand.
But it identified a number of major biosecurity shortcomings and today One News has discovered a surprising sequence of events which occurred in the lead up to the outbreak.
In mid 2009 a 4.5 kilogram consignment of kiwifruit plants called Anthers arrived in New Zealand from China, against import rules. And in mid 2010 a 1kg package of pollen also arrived from China, just four months before Psa was detected in a Te Puke orchard.
Both of these shipments were delivered to a pollen importing company based in Te Puke and the first discovery of Psa was made in an orchard situated across the road from where the company's owners live.
The imported Anthers cannot be tested because the pollen company discarded them but the pollen from the second package was retrieved and tested positive for Psa.
The Ministry for Primary Industries could not say if it can rule out this import as the cause of the outbreak.
"We don't know how Psa got into New Zealand," MPI director general Wayne McNee said.
"There were process failures here and the systems need to be improved so we clearly can do better and there are some things we need to improve on."
Otago University biochemist Russell Poulter said it could be how the virus got through.
"You could say, well that's just a coincidence, but it helps persuade the case that in actual fact it was that Chinese Anther import that was the case," he said.
It's estimated the outbreak of Psa in New Zealand kiwifruit orchards has cost $400 million.
Some kiwifruit growers are considering taking legal action.