Hei Seki, a member of Japan's parliament, was sanctioned in September by China and banned from entering the country for "spreading fallacies" on issues such as Taiwan, Hong Kong and disputed islands.

China claims Taiwan is part of its territory and has an ongoing spat with Tokyo over islands in the East China Sea claimed by both countries, and considers foreign criticism on sensitive political topics to be acts of interference.

"The fact that I am able today to smoothly enter Taiwan... fully demonstrates that the People's Republic of China and the Republic of China are completely two different countries," Seki told reporters, using Taiwan's official name.

"I came to Taiwan today, first of all, to prove this point, and to tell the world that Taiwan is an independent country," he said.

China's foreign ministry spokeswoman Mao Ning told reporters at a press briefing the "rantings of petty villains aren't worth responding to."

Seki will attend a banquet on Tuesday, along with Taiwanese Premier Cho Jung-tai, the Indo-Pacific Strategy Thinktank in Taipei, which is hosting Seki's visit, said.

China's foreign ministry said previously that Seki, a naturalised Japanese citizen, had "spread false information, colluded with Japanese anti-China forces, and wantonly attacked and smeared China".

The ministry also cited visits by Seki, who is also known by his Chinese name Shi Ping, to the Yasukuni Shrine, which honours Japan's war dead including several World War II war criminals.

China has said it would freeze Seki's assets in the country, forbid Chinese entities from conducting transactions with him, and deny entry visas to him or his family.

Japanese officials said at the time that Seki was the first Japanese lawmaker to be sanctioned by the Chinese government and that Tokyo had lodged a protest with China to demand it withdraw the measures.

While Japan and Taiwan do not have formal diplomatic ties, Japanese lawmakers often visit the democratic island.