Gay couples in Taiwan plan a mass wedding registration after politicians voted to legalise same-sex marriage.

The vote made Taiwan the first place in Asia with a comprehensive law both allowing and laying out the terms of same-sex marriage and followed two decades of campaigning.

Taiwanese President Tsai Ing-wen, a supporter of the law, tweeted: “On May 17th, 2019 in Taiwan, LoveWon. We took a big step toward true equality, and made Taiwan a better country.”

At least 20 same-sex couples are planning a mass marriage registration in Taipei on May 24, a spokesman for the advocacy group Marriage Equality Coalition Taiwan said.

The newlyweds and hundreds of invitees will hold a mass party a day later on a blocked-off boulevard outside the presidential office, the event organiser said.

The law will give a boost to Jay Lin and his partner, who hope to marry and assume joint custody of their two two-year-old sons. They plan to register after May 24.

Pictures Of The Week Photo GalleryPeople cheer outside the Legislative Yuan in Taipei (Chiang Ying-ying/AP)

“A lot of gay parents are excited about that already,” said Lin, a Taipei-based online streaming service founder.

“I think once more people are married and more families are more comfortable being out in public, that will naturally have a beneficial impact on society and on people’s minds,” Lin said.

Thousands of people, including same-sex couples, demonstrated on Friday morning in the rainy streets outside parliament before the vote.

Taiwan Same-Sex MarriageSame-sex marriage supporters gather outside the Legislative Yuan in Taipei (Chiang Ying-ying/AP)

Many carried rainbow-coloured placards reading “The vote cannot fail.”

About 50 opponents sat under a tent outside parliament and gave speeches favouring marriage between only men and women.

Religion, conservative values and political systems that discourage LGBT activism have slowed momentum toward same-sex marriage in many Asian countries from Japan through much of Southeast Asia, although Thailand is exploring the legalisation of same-sex civil partnerships.

“This will help spark a debate in Thailand, and hopefully will help Thailand move faster on our own partnership bill,” said Wattana Keiangpa of the Asia Pacific Coalition on Male Sexual Health.

Phil Robertson, deputy Asia director for Human Rights Watch, said Taiwan’s action should “sound a clarion call, kicking off a larger movement across Asia to ensure equality for LGBT people and pro-active protection of their rights by governments throughout the region.”

Taiwan Same-Sex MarriageA same-sex marriage supporter kisses a flower (Chiang Ying-ying/AP)

Taiwan’s acceptance of gay and lesbian relationships began in the 1990s when leaders in today’s ruling Democratic Progressive Party championed the cause to help Taiwan stand out in Asia as an open society.

Although claimed by China as its own territory, Taiwan is a self-governing democracy with a vibrant civil society dedicated to promoting rights for sexual and ethnic minorities, women, the handicapped and others.

Mainland China, ruled by the authoritarian Communist Party, remains much more conservative and officials have repeatedly discouraged even the discussion of legalising same-sex marriage.