The Opposition would fast-track plans to buy new Offshore Combatant Vessels (OCV) - a multi-purpose warship displacing up to 2000 tonnes and capable of long-endurance border protection tasks.
Defence White Paper plans specify an order for 20 OCV multi-purpose small warships to replace the Armidale patrol boats, mine hunters and survey ships.
Senator Johnston says the Armidale patrol boats are over-worked and unsuited to their current task of asylum seeker search and rescue and escort.
"We need to look at the versatile type of off-shore combant vessel - that is where we need to start, by looking at what they can do in terms of assisting and probably filling that gap."
Senator Johnston said he was particularly impressed with the US Navy's Littoral Combat Ship (LCS), a cutting edge trimaran designed by WA-shipbuilder Austal.
The Opposition's plans received a cautious endorsement from the Navy League of Australia, a lobby group made up of mostly retired naval officers.
A scaled down version of the LCS incorporating modular mission features offered a good solution to replace the Navy's patrol boat, survey and mine hunter fleet, said League spokesman Graham Harris.
"Certainly the OCVs under study are significantly larger (than the Armidale patrol boats) and we would definitely support their acquisition in due course.
"The OCVs are designed to be patrol vessel, hydrographic vessel or mine hunter," he said.
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