The latest battle in the state's "biological arms race" against rabbits will soon commence through a new strain of the deadly calicivirus.

The new rabbit haemorrhagic disease virus strain developed in Korea, pending regulatory approval, will be released as part of a national offensive.

WA rabbits have regathered their strength in numbers since the previous release of a 1996 version of the calicivirus. Credit:Melissa Adams

RHDV K5 is a "unique opportunity" to get the better of the rabbit plague, Department of Agriculture and Food WA officer Susan Campbell said.

It was capable of overcoming the rabbits' natural defence, a benign form of the virus, particularly in the wetter and cooler South West.