Keke, a violent warlord who emerged out of the civil war between militants from Guadalcanal and neighbouring Malaita about three years ago, has been reported to be a prime target for Australian troops and police in the Solomons.

Goff told reporters "an invitation" would be made to Keke and his supporters to give themselves up.

If that failed, efforts would be made to arrest him "but clearly those efforts would have to be backed by armed force."

Goff described the warlord as "a man probably responsible for 50 deaths, the burning of hundreds of homes, destruction of villages and who currently holds several dozen people as hostage."

"That obviously is a total collapse of the rule of law. Again that can't be allowed to continue," Goff said.

The minister said Keke's capture was "necessary" and a priority for New Zealand.

New Zealand is to contribute up to 40 police and 200 troops to a New Zealand and Australian-led peacekeeping force that could arrive in the lawless islands this month.

The formal cabinet decision has yet to be made on the deployment while the Solomons government also has to formally invite the force into the country.

Legislation also has to be passed by the Solomons parliament allowing outside forces to operate on its territory.

Goff said a "collapsed state" like the Solomons could become a haven for drug traffickers, arms and people smuggling as well as potential terrorism.

The situation has enabled groups, including Keke's, to behave "in a terrorist way," he said.

WAR.WIRE