Australian and United States quarantine authorities say they will continue to accept shipments of New Zealand kiwifruit, but are blocking imports of kiwifruit nursery stock from New Zealand, including budwood and vine cuttings.
The ban follows the potentially devastating outbreak of a vine canker disease in the Bay of Plenty.
The bacterial disease pseudomonas syringae pv actinidiae, known as PSA, has been confirmed in two orchards.
New Zealand continues to accept similar nursery stocks from Italy, where the disease has severely damaged kiwifruit - particularly gold cultivars such as Zespri's Hort16A - over the past two seasons.
Until 1996 the Ministry of Agriculture and Forestry required imports of nursery stock to be tested for the disease by one of two available DNA methods, but changed when one was found to be unreliable.
The remaining test is now required in combination with growing the imported material for at least six months in quarantine, with at least four inspections.
Earlier this year, after the PSA disaster in the Italian kiwifruit crop, New Zealand's import requirements were again reviewed, and MAF said "new information has shown that a more appropriate (DNA) testing method is now available".
MAF told NZPA it would review the import requirements for kiwifruit nursery stock based on this new information.
In Australia, a biosecurity official, Rona Mellor, told AAP that imports of kiwifruit plants were suspended pending a review on that side of the Tasman.
An Opposition agriculture spokesman John Cobb called for the Australian government to stop imports of kiwifruit, but Ms Mellor said the disease appeared to affect vines rather than fruit.
So far, MAF has issued three orchards with a "restricted place notice", including two neighbouring Hort16A properties over the road from one another, which have both been confirmed as infected.
A total of 43 growers have emailed photos of apparent symptoms on their vines, and 18 orchards are being investigated by MAF.