Notification that the new rabbit haemorrhagic virus disease strain, RHDV1 K5, has been approved for release is a huge relief for farmers plagued by the pest.

Andrew Simpson, a high country farmer who represents Federated Farmers on the cross-sector group co-ordinating the K5 initiative, said there are some desperate farmers out there.

"The timing of this is critical in some areas. If another year goes by without release of this virus, the ecological damage to some properties would be mind-numbing."

K5 is the Korean strain of the RHDV1 rabbit calicivirus that was released in Otago in 1997 without official sanction. The new K5 strain will help overcome resistance to the old virus that has built up among wild rabbit populations.


"K5 was introduced into Australia last year and reports to date are that it has been very effective, better than anticipated," Andrew said. "Knockdown (wild rabbit kill) rates are averaging above 40 per cent at the moment, and in some areas they're achieving up to 80 per cent."

For the greatest hit rates, it's important the K5 strain is released among local pest rabbit populations in March and April. It had been hoped New Zealand could use data from the Australian approval application so that release here could have occurred in March 2017, but the time frames to get all the documentation required by the Ministry for Primary Industries in place proved too tight. All approvals have now been gained.

Andrew said a comprehensive strategy is in place to release the new virus in districts around New Zealand, in an operation to be run by regional councils with input from land owners and other stakeholders in the Rabbit Co-ordination Group.

"No-one is under the illusion this is the silver bullet to deal to wild rabbit populations once and for all. Farmers and councils will have to continue with the other forms of rabbit control that they've employed for years.

"But with the carefully planned strategy we have in place, there is confidence this will put a major hit on what is a very expensive and environmentally damaging pest, particularly in Otago, North Canterbury, the McKenzie, the High Country, Marlborough and Hawke's Bay."