Taiwan lawmakers have approved a same-sex marriage bill, making the island nation the first Asian country to legalise gay marriage.

Thousands of supporters of same-sex marriage gathered in Taipei, the capital, outside parliament, which voted on a series of bills offering same-sex couples similar legal protections for marriage as heterosexuals.

Friday's vote followed a long debate over marriage equality.

In 2017, the democratic island's constitutional court declared same-sex couples had the right to legally marry, and set a deadline of May 24 for legalisation.