China on Wednesday condemned former Japanese prime minister Taro Aso's visit to Taiwan, urging Tokyo to refrain from interfering in China's internal affairs or lending support to the "Taiwan independence" separatist forces in any form.

Aso, also the vice-president of Japan's ruling Liberal Democratic Party, met with Taiwan leader Tsai Ing-wen and deputy leader Lai Ching-te during his three-day visit starting on Monday.

He delivered a speech in Taipei saying there should be no war in the Taiwan Strait, and called for a posture of strong deterrence and "readiness to fight".

Aso is the most senior Japanese political figure from his party to visit Taiwan since 1972, when Tokyo ditched ties with Taiwan and established diplomatic relations with the People's Republic of China.

Despite China's opposition, a certain Japanese politician's move sought to hype up cross-Strait tensions, stoke antagonism and confrontation, and blatantly interfere in China's internal affairs, the Foreign Ministry said in a statement.

China has made serious demarches to Japan over the visit, saying it violates the one-China principle and the spirit of the four political documents between China and Japan and tramples on the basic norms governing international relations.

The Japanese politician kept raising the possibility of "a war" while in Taiwan, an obvious attempt to stir up trouble in the Taiwan Strait and push the people in the Taiwan region over the edge of an abyss, a Foreign Ministry spokesperson said in the statement.

"What makes this Japanese politician think he is in a position or has the confidence to make such unwarranted remarks on Taiwan?" the spokesperson said.

No one should underestimate the strong resolve, will and capability of the Chinese people to defend the nation's sovereignty and territorial integrity, the statement said.

The spokesperson urged Japan to reflect on its history of aggression, and abide by the one-China principle and its commitments regarding the Taiwan question.

The spokesperson also warned the Taiwan authorities that "Taiwan independence" has no future, and soliciting Japan's support and selling Taiwan away will only harm the people in Taiwan.

Any attempt to collude with external forces in seeking independence and provocations will only fail, the spokesperson said.