US President-elect Donald Trump speaks during a news conference in Trump Tower, Manhattan, New York, US, January 11, 2017. Photo: Reuters

China said on Sunday that its one-China policy is "non-negotiable" after President-elect Donald Trump suggested that he might use American policy on Taiwan as a bargaining chip between the two sides.

China Foreign Ministry spokesman Lu Kang reiterated in a statement that the "government of the People's Republic of China is the only legitimate government representing China."

"That is the fact acknowledged by the international community and no one can change," Lu added.

Since recognizing Beijing in 1979, Washington has maintained only unofficial ties with Taiwan, the self-governing island that Beijing considers its territory.

Trump broke with decades of precedent last month by taking a congratulatory telephone call from Taiwan's leader Tsai Ing-wen and has since cast doubt on America's commitment to a "One China" policy that recognizes the island as a part of China. Beijing considers any reference to a separate Taiwanese head of state to be a grave insult.

Trump told the Wall Street Journal on Friday that "everything is under negotiation, including 'one China.'" The interview is the latest indication Trump that he will shake up the US-China relationship, particularly on Taiwan, which China considers a core national interest.

Trump then said in a television interview that he didn't feel "bound by a one-China policy unless we make a deal with China having to do with other things, including trade."

On Sunday, Reince Priebus, Trump's incoming chief of staff, said that "there are no plans to change the one-China policy."

"But certainly that policy is on the table if China doesn't also come to the table and work with us on trade, work with us on the South China Sea and what's happening there," Priebus said on ABC's "This Week".

After attacking China repeatedly during his campaign, Trump has continued to disparage China on his Twitter account over its military build-up in disputed areas of the South China Sea, allegedly manipulating its currency to put American companies at a disadvantage, and not doing enough to curb North Korea's nuclear program.

He has also announced that a new White House trade council will be led by economist Peter Navarro, a sharp critic of Chinese economic policy who wrote a book titled "Death By China."

Trump told the Wall Street Journal that he would not label China a currency manipulator as soon as he takes office, though he repeated his contention that China is manipulating the yuan.

Chinese political observers said on Sunday that they expect Beijing's response to change once Trump is inaugurated next week.

"Trump has not taken office yet, so he is an ordinary person now," said Shen Dingli, a professor of international relations at Fudan University. "Therefore, there's no need for China to take his remarks seriously or further respond to what he said."

Tang Yonghong, a professor at Xiamen University, said that China needs to convince Trump that "if he wants to make money from the Chinese mainland, he must be a friend of China instead of being an enemy."

"I think Trump is handling international relations, including Sino-US relations, with a businessman's logic," Tang said. "He wants to see how China will respond to such provocation."

'Take off the gloves'

So far, Beijing has reiterated its refusal to negotiate on Taiwan and to push for positive cooperation between the two sides, though state-run media have run several strongly worded editorials attacking Trump.

"If Trump is determined to use this gambit in taking office, a period of fierce, damaging interactions will be unavoidable, as Beijing will have no choice but to take off the gloves," the English-language China Daily said.

The China Daily said that Beijing's relatively measured response to Trump's comments in the Wall Street Journal "can only come from a genuine, sincere wish that the less-than-desirable, yet by-and-large manageable, big picture of China-US relations will not be derailed before Trump even enters office".

But China should not count on the assumption that Trump's Taiwan moves are "a pre-inauguration bluff, and instead be prepared for him to continue backing his bet".

"It may be costly. But it will prove a worthy price to pay to make the next US president aware of the special sensitivity, and serious consequences of his Taiwan game," said the national daily.