The Greens are seeking a debate on a reported plan to expand American troops in Australia. Greens leader Senator Bob Green said it is Parliament's duty to debate the pros and cons of a wide U.S. military presence in the country.

There are reports that part of the official visit of U.S. Barack Obama this week to Australia is to announce that the country would bring more troops to strategic areas in the Asia-Pacific region including Darwin and to hike the number of joint exercises and training. The White House has declined to comment on the report.

"We are putting a clear point of view that Parliament should debate new foreign troop placements in Australia, whether they be in Darwin or Western Australia or anywhere else and that of course is responsible democracy," ABC News quoted Mr Brown.

Australian Prime Minister Julia Gillard, who is in Hawaii attending the Asia-Pacific Economic Conference, declined to provide details about the U.S. plans.

"Of course we'll be reflecting on the fact that it's the 60th year of ANZUS, 60 years of being allies and what being allies means to the future.... On any specifics of what I may announce with President Obama when he's in Australia, we'll leave that to when we're in Australia," Ms Gillard said.

The Telegraph reports that Mr Obama will station between 500 and 1,000 Marines at the Robertson Barracks in Darwin and will expand the U.S. navy's use of bases at the Northern Territory capital and in Perth, Western Australia.

The Darwin barracks would be the nearest mainland Australian military base to China and beyond the widening range of new Chinese missiles which can reach the main U.S. Pacific bases in Okinawa Island in Japan and the island-territory of Guam. The troops assigned there would likely be on a rotation basis, not permanent deployment.

Former senior Australian defence official Hugh White, however, warned of the risks of allowing wide American troop presence in Australia.

"In Washington and in Beijing, this will be seen as Australia aligning itself with an American strategy to contain China.... In the view from Beijing, everything the U.S. is doing in western Pacific is designed to bolster resistance to the Chinese challenge to U.S. primacy," Mr White told the Sydney Morning Herald.

Australian Foreign Minister Kevin Rudd, however, defended the planned expansion.

"From the Australian perspective, here we are with a vast coastline, a population of just 23 million. It has always made national security sense to have a strong security alliance with America," The Telegraph quote Mr. Rudd.