China has urged Washington to block the president of Taiwan from passing through the US, after reports saying she may stop in New York next month on her way to Central America.

Taiwan has diplomatic relations with 22 states and the island's leaders make regular visits to its small group of allies in Central America and the Caribbean, often stopping in the US for meetings with sympathetic lawmakers.

Taiwan's Liberty Times reported that President Tsai Ing-wen may seek to meet with key members of Donald Trump's team while in New York on her way to Nicaragua, Guatemala and El Salvador, though her office could not confirm the trip to AFP.

China's foreign ministry called on the US to block her transit.

Tsai's “true intention is self-evident”, it said in a fax to AFP Wednesday.

“We hope America abides by the principle of the One China policy and the three US-PRC Joint Communiques and does not allow her transit.”

It further warned against Washington giving an “erroneous signal to 'Taiwanese independence' forces”.

The news comes after president-elect Trump broke decades of precedent and accepted a congratulatory phone call from Tsai, angering Beijing, which regards the democratically-ruled island as a rogue province awaiting unification, by force if necessary.

Official reaction from Beijing has been muted, but China often uses state media to telegraph its policy positions and the Global Times newspaper blasted Trump Tuesday for his “inability to keep his mouth shut”, damning his “provocation and falsehoods”.

Although the United States is Taiwan's main ally and arms supplier, it has not had official diplomatic relations with Taiwan since 1979, when it switched recognition from Taipei to Beijing.

Asked about Tsai's visit, a US State Department spokesman said at a briefing that such transits were in keeping with “longstanding US practise” and noted the US “usually” allows Taiwan's leaders to pass through the country.

Tsai visited Panama and Paraguay in June in her first overseas trip a month after taking office with stopovers in Miami and Los Angeles. Beijing protested to Washington over the trip as Tsai met with US politicians in Miami.

Previous presidents of Taiwan have also transited the US, with Tsai's predecessor Ma Ying-jeou stopping in Hawaii in 2014 and Boston in 2015.

Taiwan has haemorrhaged allies in recent decades as they jumped ship to align with an ascendant China.