Beijing: Chinese President Xi Jinping has insisted that mainland China and Taiwan be united into one nation in the clearest sign yet that he wants to settle the 70-year dispute during his tenure.

"China must and will be united, which is an inevitable requirement for the historical rejuvenation of the Chinese nation in the new era," Xi told a gathering in Beijing to mark the 40th anniversary of a landmark Beijing overture to Taipei after the US and China established relations.

Chinese President Xi Jinping arrives for an event to commemorate the 40th anniversary of the Message to Compatriots in Taiwan. Credit:AP

To do so, China and Taiwan should enter into "in-depth democratic consultations", he said.

But Taiwan's President Tsai Ing-wen hit back, saying the island would not accept a "one country, two systems" political arrangement with China, while stressing all cross-strait negotiations needed to be on a government-to-government basis.