China offered its sternest rebuke yet to Donald Trump, saying anyone who challenges Beijing's interests in Taiwan will "lift a rock only to crush his own toes".

"If he tries to sabotage the One China policy or harm China's core interests, ultimately he will lift a rock only to crush his own toes," Chinese foreign minister Wang Yi said Monday in Switzerland according to comments posted on the ministry's web site.

China is closely monitoring developments, he said, issuing a warning against "any person or force in the world" looking to play tough with Beijing on Taiwan.

The comments come after Trump said he could jettison Washington's decades-old "One China policy" -- a diplomatic dodge allowing the US to simultaneously do business with Beijing and Taipei.

On Tuesday Chinese media sent another fusillade toward the "presumptuous and ill-guided" president-elect, slamming his approach to Taiwan as a recipe for disaster.

"Beijing should be prepared for the worst-case scenarios, particularly regarding Taiwan, as a presumptuous and ill-guided Trump looks set to usher in an era of turmoil," the state-run China Daily said in an editorial accompanied by a cartoon of the billionaire politician sitting on a powder keg.

"Trump's bloated and bloating ego may prevent him from seeing that is the likely outcome that lies ahead if he persists with this gamble."

China regards self-ruling Taiwan as part of its own territory awaiting reunification under Beijing's rule.

The nationalistic Global Times newspaper warned Trump in its editorial Tuesday that "pride goes before a fall", and said he had lost the "strategic initiative" by revealing his strategy of "blackmailing" China.

"Especially in the Taiwan Strait, China is now confident enough to arm-wrestle with Trump," it said.

Trump shocked the diplomatic establishment and angered Beijing by speaking directly with Taiwan's leader Tsai Ing-wen after his election victory.

After fierce criticism of the move, he upped the ante, taking to Twitter to ask why he should not be allowed to speak to Tsai, then attacking Chinese foreign and economic policy.

On Sunday, he went a step further, saying he did not see why Washington must "be bound by a One China policy unless we make a deal with China having to do with other things, including trade."

The remarks were a step too far for Beijing, which had initially seemed resigned to taking a wait-and-see approach to the president-elect.

Trump's comments also earned a rare rebuke from the White House, with spokesman Josh Earnest warning the president-elect that Taiwan is not a "bargaining chip".