Growers caught up in a biosecurity storm say they feel "vindicated" after the Ministry for Primary Industries confirmed thousands of imported plants did not pose a risk after all.

MPI seized tens of thousands of apple and stonefruit (peach, plum and nectarine) plants in March, following an MPI audit which found a number of significant failures at Clean Plant Centre Northwest in the United States.

Five parties, including four Hawke's Bay growers and nurseries, launched a High Court review of the action, which the industry said would have resulted in up to $1 billion in losses.

However, MPI director of plant and pathways Pete Thomson confirmed about 20,000 apple plants and 400 stonefruit plants imported from a US testing facility had now been released from all restrictions.

Apple and stonefruit trees were affected. Photo / File
Apple and stonefruit trees were affected. Photo / File

"As all the test results were negative and we are satisfied the biosecurity risk has been minimised, we're pleased to be in the position to release these plants back to their owners," Thomson said.

"Throughout this process our decisions have been based on protecting New Zealand. Some of the diseases, if present, could impact significantly on our wider horticultural industry."

Nearly 20,000 stonefruit plants still required further testing over spring and summer, when diseases of concern will be most evident if they are present.

MPI had worked with affected nurseries, importers and growers to develop detailed individual testing plans for each owner.

Almost 48,000 affected apple and stonefruit plants and small trees were secured at 50 sites in Hawke's Bay, Waikato, Nelson and central Otago. In total, 32 nurseries, importers and growers were affected.

He also pointed out that just over 1000 apple plants had been voluntarily destroyed by 12 owners. Twenty owners opted to destroy more than 6000 stonefruit plants.

"MPI remains open to receiving requests for payment for direct and verifiable losses incurred as a result of destroyed or contained plant material," Thomson said.

"We've written to all affected owners on this, and we are offering one-on-one meetings to talk through the process."

The five industry players, Johnny Appleseed Holdings - Yummy Fruit Company (Hastings), McGrath Nurseries (Cambridge), New Zealand Fruit Tree Company (Hastings), Pattullo's Nurseries (Napier), and Zee Sweet (Hastings) - sought a judicial review of the original MPI directive, which was ruled to be "unlawful" in August.

NZ Apples and Pears chief executive Alan Pollard. Photo / File
NZ Apples and Pears chief executive Alan Pollard. Photo / File

Group spokesman Andy McGrath said the group was encouraged by MPI's announcement and the release of the apple plants and plant materials.

"We feel this has vindicated the position we have taken since the very beginning of this issue.

"This is the first step towards rectifying the unlawful actions imposed by MPI, but there is still some way to go before orchardists and nurseries are able to return to normal commercial production."

McGrath said he had recently returned from a visit to the US-based plant facility that has supplied New Zealand orchards and nurseries with new plant varieties for over 30 years, and he was hopeful the facility was willing to consider re accreditation.

Yummy Fruit Company general manager Paul Paynter said it was a satisfying outcome for the Hastings-based company.

"Yesterday, was the day we had our prisoners of the government released, so it was a good result.

"We have some new varieties that we believe are the future of the apple and stonefruit industry and can really change our industries. They have really big export potential and we have them back from where they were going to be destroyed.

"In the new year we will start a propagation programme to lay the foundations for our future prosperity and hopefully, many others in the industry."

NZ Apples and Pears chief executive Alan Pollard said the release of the material was "very good news".

"A comprehensive independent economic analysis identified that the total destruction of all material would have led to losses to the pipfruit and summer fruit industries in excess of $1 billion.

"There is still a lot of work to do to ensure that there is no repeat of this situation in the future, and we are looking forward to working with MPI on reviewing and improving the plant import pathway."