Beijing has urged the United States to exercise caution as it refocuses its defence policy to counter China's rising military power and growing assertiveness in Asia.

China's defence ministry said a new US military strategy unveiled by President Barack Obama last week was based on "unfounded" charges, and insisted its rise presented "an opportunity, not a challenge" to Washington.

"There is a movement towards greater peace and stability across the Asia-Pacific region," said spokesman Geng Yansheng in a statement published on the ministry website late Monday.

"We urge the United States to follow the prevailing trend, take an objective and balanced view of China and its military and behave cautiously and in a manner conducive to developing good relations."

Geng's comments came hours after China's foreign ministry said the new US defence strategy was based on "groundless" and "untrustworthy" charges, and insisted it posed no threat to any nation.

Washington's focus on Asia is fuelled by concerns over China's growing navy and its arsenal of anti-ship missiles that could jeopardise US military dominance in the Pacific.

China is highly secretive about its military spending, but its People's Liberation Army has benefited from a huge and expanding budget boosted by the nation's rapid economic growth.

However, China's responses to recent US moves to boost its military presence in Asia -- including the deployment of up to 2,500 Marines to northern Australia -- have been relatively restrained.

China's official Xinhua news agency said last week it welcomed a larger US presence in Asia as "conducive to regional stability and prosperity", while urging it against "warmongering".