Taiwanese voters are deciding whether to remove about one-fifth of their lawmakers from the opposition Nationalist Party.

Voters in Taiwan were casting ballots on Saturday on whether to recall one-fifth of the island's parliament, all from the major opposition party, in a move supporters hope will send a message to China and opponents say is an assault on democracy.

Taiwanese voters turned out at schools, churches and community centres to cast their ballot in a high-stakes recall election that could give President Lai Ching-te's party control of the parliament.