Hong Kong's government proposed legislation this summer to recognise some rights for same-sex partners, but only for those whose unions are registered abroad.

Despite LGBTQ activists decrying its limitations, the proposal drew near-universal criticism from the pro-Beijing politicians that dominate Hong Kong's legislature.

Only around a dozen lawmakers within the 89-member council have publicly declared their support so far.

"How far will Hong Kong lag behind? Today is a key moment," LGBTQ activist Jimmy Sham told AFP, noting that other Asian jurisdictions have set up legal protections for same-sex couples.

Sham launched a legal bid for Hong Kong to recognise same-sex marriage in 2023, but it was quashed by the city's top court.

However, the court ordered the government to create an "alternative framework" for LGBTQ couples -- the subject of Wednesday's vote.

Sham was sitting in the legislature's public gallery ahead of the vote, closely watched by security guards.

"Persevering in (LGBTQ activism) for such a long time increasingly requires a kind of naivete," he said.

The government has stressed that marriages in Hong Kong will remain defined as a union between a man and a woman, but in July proposed a registration system for same-sex couples whose partnership is legally recognised abroad.

Registered couples will enjoy more rights in medical-related matters and after-death arrangements -- for example, visiting a partner in hospital or claiming their body after death.

Despite the bill falling "significantly short of international human rights standards", Amnesty International urged lawmakers to adopt it as a step forward.

- 'Stable and harmonious' -

The current batch of Hong Kong lawmakers has never shot down a government bill.

But in a rare rift, the proposal has been condemned by the city's top three pro-establishment parties, who say it defies traditional family values.

Same-sex marriage is not legal in China and social stigma remains widespread.

Hong Kong is a special administrative region of China with its own legislature and a mini-constitution that guarantees a "high degree of autonomy".

However, the city's once vibrant political opposition and civil society have been effectively silenced since Beijing introduced a sweeping national security law in 2020.

Authorities gave the public seven days to write in with their views on Wednesday's bill.

Of the 10,800 submissions received, 80 percent were against, according to the government.

The findings sharply contrast with a 2023 survey carried out by three universities that found 60 percent of those polled support same-sex marriage.

Advocacy group Hong Kong Marriage Equality said around half the submissions opposing the bill used templates that indicate "strong mobilisation by specific groups".

"(The government) must not allow people with ulterior motives to wield slogans of equality to threaten Hong Kong's stable and harmonious society," read one.

Outside the legislature on Wednesday morning, two members of a religious group displayed a banner calling on lawmakers to keep marriage between heterosexual couples.

A joint letter issued Monday and signed by 30 Asian LGBTQ rights groups called on the government to "publicly disclose a contingency plan" and introduce a revised proposal if the bill is vetoed.