Japanese military forces will begin regular deployments to the Northern Territory, to train with both Australian and U.S. troops.
It comes as part of a co-operation effort with the United States over growing concern about China’s military power in the Indo-Pacific region.
About 2,000 U.S troops are already stationed in the N.T. annually.
Once deployed, Japan’s amphibious rapid deployment brigade will begin training with the Australian Defence Force and the US Marines.
Australia's acting prime minister and Defence Minister Richard Marles, U.S. Defence Secretary Lloyd Austin and Japanese Defence Minister Gen Nakatani all made the announcement on Sunday from Darwin.
In a joint statement the trio said the partnership played a “critical role” in upholding regional stability and committed to consulting on regional security issues.
They also emphasised having serious concerns about Chinese military activity in the region, especially actions in the China majority-claimed South China Sea.
When questioned about Beijing’s possible reaction to the deployment, Marles said the decision was made purely to build “the best relationships possible with like-minded countries, with our friends and with our allies.”