A Hong Kong court has dismissed a government bid to deny same-sex married couples the right to rent and own public housing, saying that it was "discriminatory in nature" and a complete denial of such couples' rights.

The ruling by Hong Kong's Court of Appeal on Tuesday is the latest in a series of legal breakthroughs for gay rights advocates in the global financial hub this year.

The government had challenged two High Court rulings that it was "unconstitutional and unlawful" for the city's housing authority to exclude same-sex couples who married abroad from public housing.

The appeal involved two cases, one in which the authority had declined to consider a permanent resident's application to rent a public flat with his husband, because their marriage in Canada was not recognized in Hong Kong.

The other involved a same-sex couple who were denied joint-ownership of a government-subsidized flat by the authority because their marriage in Britain was not recognized in Hong Kong.

Court of Appeal justices Jeremy Poon, Aarif Barma and Thomas Au said in a written judgment that the authority's treatment of gay married couples was "discriminatory in nature" and they should be afforded equal treatment.

"The differential treatment in the present cases is a more severe form of indirect discrimination than most cases because the criterion is one which same-sex couples can never meet," the judges said in their ruling.

One of the men involved in the second case, Henry Li, welcomed the ruling in a post on Facebook.

Rights group Hong Kong Marriage Equality also welcomed the decision saying it had made clear "that discrimination and unequal treatment on the ground of sexual orientation has no place in public policy decisions."

Hong Kong's top court in September ruled against same-sex marriage but acknowledged same-sex couples' need "for access to an alternative legal framework in order to meet basic social requirements."

The government was given two years to come up with the framework.

A Hong Kong court in September sided with a married lesbian couple who argued that both women should have parental status over their child born via reciprocal IVF.

Activists in other parts of Asia are watching Hong Kong's courts in the hope that their rulings could influence campaigns for reform elsewhere.