A Chinese warship will soon join Australian and US forces in military exercises off Darwin, despite ongoing tensions in the disputed South China Sea.

The ABC has learned Beijing has indicated it will deploy "a major fleet unit" to Exercise KAKADU during late August until mid September, the first time the Chinese have taken part in the Australian war games.

China's inaugural participation in the KAKADU maritime drills comes just months after the US "uninvited" the People's Liberation Army from taking part in similar exercises off Hawaii known as RIMPAC.

In April, the ABC revealed three Australian warships were confronted by the Chinese military as they travelled through the South China Sea.

Last year, the ABC also revealed a high-tech Chinese spy ship was monitoring the Talisman Sabre joint military exercises between Australia and the United States off the Queensland coast.

Twenty-seven nations have accepted invitations to join or observe the KAKADU exercises including Cambodia, Indonesia and The United Arab Emirates, but the United Kingdom has declined to take part.

In a statement, the Defence Department described this month's activity as "the Royal Australian Navy's premier maritime exercise" which seeks to "generate active and effective security partnerships between Australia and our region".

A senior Defence source has told the ABC the Chinese warship is expected to conduct some training alongside Australian and American vessels, but would be excluded from certain activities for "security reasons".

The Chinese warship's impending arrival in northern Australia comes three years after security concerns were raised at the highest levels in Defence about the decision to lease the Port of Darwin to the Chinese-owned company Landbridge.

Exercise KAKADU 2018 will take place in Darwin and in northern Australia from 30 August 15 September, with over 2,000 military personnel participating.

Held every two years, Exercise KAKADU aims to "build and strengthen mutual understanding and interoperability in the maritime domain through a series of training and engagement activities".