The ruling comes after a landmark 2023 decision -- also by the Court of Final Appeal -- shut the door on legalising same-sex marriage, but gave the government two years to set up a framework for other rights for such couples.

It marked the end of a six-year legal battle that began when resident Nick Infinger took the government to court over a policy that excluded him and his partner from public rental housing on the grounds they were not an "ordinary family".

The case was later heard together with that of Henry Li and his late husband, Edgar Ng, who challenged government policies on subsidised housing and inheritance rules that barred same-sex couples.

"The Court unanimously dismisses" the appeals brought by the Hong Kong government, chief judge Andrew Cheung wrote in two court rulings.

Advocacy group Hong Kong Marriage Equality applauded Tuesday's court rulings and urged the government "to immediately end the exclusion of same-sex couples from marriage".

Support for same-sex marriage in Hong Kong has grown over the past decade and hit 60 percent last year, according to a survey conducted jointly by three universities.

LGBTQ activists say they hope the mandated upcoming framework can protect rights in a more comprehensive way, instead of them relying on incremental victories in court.

The government told AFP in September that it "has been studying the range of issues involved and formulating implementation details" on protecting same-sex couples' legal rights.

- Housing and inheritance -

In his ruling, chief judge Cheung said policies that excluded same-sex couples from public rental flats and subsidised flats sold under the city's Home Ownership Scheme "cannot be justified".

"(For) needy same-sex married couples who cannot afford private rental accommodation, the (government's) exclusionary policy could well mean depriving them of any realistic opportunity of sharing family life under the same roof at all," Cheung added.

Public rental flats house around 28 percent of the city's 7.5 million people.

Lawyer Monica Carss-Frisk, representing the government, argued in an October hearing that housing policy was designed to support "procreation" among opposite-sex partners.

But Cheung responded at the time that opposite-sex couples without children were allowed to apply for public housing, many with no plans for offspring.

On the issue of inheritance, judges Joseph Fok and Roberto Ribeiro wrote in Tuesday's ruling that existing rules were "discriminatory and unconstitutional", adding that authorities had "failed to justify the differential treatment" of same-sex couples.

Under the law, same-sex couples could not benefit from the rules applicable to "husband" and "wife" when it came to distributing a deceased person's estate.

Lawyer Timothy Otty, representing Infinger and Li, had also pointed out in October that the government had undersold the difficulties faced by same-sex couples when one member dies without a will.

Infinger and Li previously had won in lower courts, but the government in February took the cases to Hong Kong's highest appeals court, where they were heard by a panel of five local judges.