Thousands of LGBTQ+ revellers and activists gathered for a parade through the capital's street as signs and placards with "Love wins" slogans were displayed across the city.

"This year's pride parade can be considered one of the biggest because it coincides with the passing of the same-sex marriage," Avorawan Ramwan said, who joined the parade with her partner.

Thailand is set to legalise same-sex marriage as an equality bill heads for the final readings in the Southeast Asian country's Senate later this month.

Thai Prime Minister Srettha Thavisin also joined the parade, dressed in a rainbow shirt.

"It is a basic right to choose who to love," he posted on the social media platform X, formerly known as Twitter.

The bill overwhelmingly passed the upper house's first reading in April and will have its second and third readings this month.

"The Senate will likely pass the bill on June 18," Senator Wallop Tangkananuruk, chairman of the Senate's committee on same-sex marriage, told Reuters.

If there are no amendments from the lower house, the government will send it for royal approval, Wallop said, adding that the law will come into force 120 days after it is published in the Royal Gazette.

"Pride events are meaningful, and Thailand is known worldwide as a paradise for the LGBT community. Therefore, we must help promote and advocate for it, as well as implement laws to support the LGBT community," said transgender woman Aunchanaporn Pilsauta.