Aust-Japan could co-operate on subs: study

AUSTRALIA and Japan could deepen defence ties by co-operating on Australia's next generation of submarines, a think tank says.

The Australian Strategic Policy Institute (ASPI) says Japan's expertise in building submarines suited to Pacific operations could be of interest to Australia as it looks to replace its six Collins boats.

Australia and Japan could also co-operate on ballistic missile defence, with Japan already fielding SM-3 missiles on its Kongo-class warships - a capability Australia is considering for its air warfare destroyers.

"In particular, Japan and Australia could increase their defence industry co-operation and ease export controls, a move that Japan has recently taken with the United Kingdom," ASPI says in a paper released on Monday.

Australia is currently examining options to replace the Collins submarine replacement, including an all-new design or an evolution of the Collins.

"The Australian government has committed to developing a submarine propulsion testbed facility, and it would work to Australia's great advantage if one of the systems tested had significant Japanese input," ASPI said.

Overall, ASPI said there were indications Australia-Japan defence relations would expand in coming decades.

"Not only because there's a desire for closer ties and a substantially shared strategic view of the world, but also because there'll be a growing need for us to work together to achieve common security goals," it added.

Japanese defence co-operation is constrained by its post-World War Two constitution.

The Australian