The two countries have rapidly developed close defence ties in recent years, and Japan considers Australia as a semi-ally, its closest security partner after the United States, its only treaty ally.

Japan’s Defence Minister Minoru Kihara and Australian counterpart Richard Marles also agreed during talks in Tokyo to step up their three-way military co-operation with the United States, the Japanese Defence Ministry said in a statement.

Kihara and Marles said that deepening their operational co-operation and joint exercises, and enhancing interoperability, were important steps in increasing their bilateral defence ties.

The two ministers confirmed that there was continuing progress in those areas under their Reciprocal Access Agreement, which took effect in August.

The agreement is aimed at breaking down legal barriers to allow troops to enter each other’s country for training and other purposes.

Other than with the United States, Japan has such defence pacts with only Australia and the United Kingdom.

Japanese Prime Minister Fumio Kishida’s government adopted a new security strategy last December that focuses on reinforcing strike capability, in a break from Japan’s postwar principle of having a military only for self-defence.

Under the strategy, Japan also aims to nearly double its military spending over the next five years, which would make it the world’s third-biggest spender after the US and China.

Japan has been building up its defence spending and military power in part to deter China in territorial disputes it has over islands that Japan controls in the East China Sea.

Australia has stepped up engagement in the South Pacific where it is concerned about China’s growing involvement, including the signing of a security pact with the Solomon Islands.

Under the new security agreement Japan and Australia are discussing exercises deploying F-35A fighter jets to both countries, the Japanese ministry said.

“The Reciprocate Access Agreement is very central to the advancement of our relationship,” Marles told Kihara during their talks on Thursday.

“From the Australian point of view, we really see, in Japan, we see our future security in the region and in the world.”

The ministers confirmed the importance of co-operating on technology and welcomed the conclusion of a contract for the joint development of laser technology by Australia’s Defence Department and Mitsubishi Electric Corp Australia, the Japanese ministry said.