SYDNEY, July 9 -- A senior Australian politician criticized on Thursday Australian-U.S. war games involving 30,000 troops currently underway in Queensland as protesters planned to again trespass on the operation's base.

Acting Greens leader Senator Scott Ludlam said the biannual Australian and U.S. "Talisman Sabre" war games were not about defending a country from an invasion, but practicing " expeditionary wars and invasions."

For the first time the Japanese military is taking part in Talisman Sabre which involves all defense forces, and Ludlam said it was sending the wrong message to neighbors.

"Most people join the ADF (Australian Defence Force) expecting that they're there for the defence of Australian territory," he told reporters at a peace conference in Brisbane on Thursday.

"That's not what they are training for, it's about landing on beaches and invading other people's countries."

Professor Richard Tanter, Australian chief of international peace think tank the Nautilus Institute, said the exercise, which is simultaneously being held near Darwin, wasn't in Australia's best security interests.

He also questioned Japan's involvement.

"These war games I think are an unwelcome increase in our integration not only with the United States but with Japan, where Japan has the most nationalist government that country has had since 1945," he said.

Peace activists have already trespassed on the main Queensland Shoalwater Bay training area, with three being arrested in the live-ammunition training area on Wednesday.

More activists are planning to campaign on the site later this week.