The US secretary of defence used his speech at an annual security forum on Saturday to warn that China was "credibly preparing" to use military force to upend the balance of power in Asia.

He added that the Chinese military was building the capabilities to invade Taiwan and "rehearsing for the real deal".

In a statement released just after midnight, China's foreign ministry said it had "lodged solemn representations with the US side" over Hegseth's comments, adding that it "strongly deplores" his remarks.

"The US should not try to use the Taiwan issue as a bargaining chip to contain China and should not play with fire," it said.

Beijing, which did not send its defence minister Dong Jun to the Singapore summit, called the "Taiwan issue" China's "internal affair" and said foreign countries had no right to interfere.

China considers the self-ruled democratic island as its territory and has not ruled out using force to take control of it.

Hegseth also accused Beijing of "illegally seizing and militarising lands" in the disputed South China Sea.

Beijing claims almost the entire waterway, despite an international ruling that its assertion has no merit.

The foreign ministry on Sunday claimed there had "never been any issue" with navigation in the waterway.

China "is committed to safeguarding its territorial sovereignty and maritime rights and interests in accordance with the law", a ministry spokesperson said.

Beijing also accused the United States of turning the Indo-Pacific region into a "powder keg" by deploying weapons in the South China Sea.