Hundreds of people took to Taipei's streets to call for the legalisation of same-sex marriage, throwing water balloons at the headquarters of the ruling party they believe is blocking a proposed amendment to the law.
The march on Saturday, bolstered by a landmark US ruling on gay unions, was aimed at spurring progress on a gay marriage bill which passed its first reading in parliament in October 2013 but has since been on ice.
In keeping with Taiwan's parliamentary system, the bill would have to start anew if it fails to pass its third reading before February 2016, the end of the current legislative session.
"If this bill cannot get the approval in the next few months, then all our previous efforts would vanish. You wouldn't be happy with that, would you?" shouted activist Hsu Hsi-wen, speaking through a loudspeaker from atop a truck to around 600 people gathered outside the headquarters of the Kuomintang (KMT) party.
"No!" the crowd shouted, enthusiastically waving rainbow flags.
The KMT is seen as reluctant to support the controversial bill for fear of angering a majority of conservative voters.
"Twenty-one countries have legalised same-sex marriage, with the US joining the chorus last month. But look at Taiwan, which claims to be one of the most friendly countries to gays and lesbians, this bill has been on ice since its first reading," said Hsu, who is the chief executive of the Taiwan Alliance to Promote Civil Partnership Rights.
After failing to draw a reaction, the crowd hurled coloured water balloons at KMT premises, which were guarded by dozens of police.
A junior Kuomintang representative later appeared to accept a petition from the protesters, with no clashes reported.
The demonstrators also marched to offices of the major opposition Democratic Progressive Party (DPP), who they say has paid only lip service in its support for the bill, and on to parliament.
Surveys show Taiwan is deeply divided over the legalisation of gay marriage.
According to a poll of 1,377 people by the cable news channel TVBS in 2013, 45 percent oppose same-sex union while 40 percent are in favour.