The first legal challenges to Hong Kong's banning of same-sex marriage has been mounted by two separate gay men.

A 21-year-old University Hong Kong student, known as TF, and a 31-year-old activist, known as STK, argued before Hong Kong's High Court that preventing same-sex couples from marrying is a violation of the city's Bill of Rights and mini-constitution, the Basic Law, South China Morning Post reports.

While the cases were brought forward last year, they only came to light on Thursday, during a preliminary hearing, where it was also revealed that STK had already married his partner in New York.

Issues of same-sex spousal visas, civil partnerships, and taxation have come before the courts, but gay marriage had never been considered until now, making this a historic moment.

This summer, a court of appeals overturned a lower court ruling in favor of civil partnership rights. That legal battle is ongoing.

In a more progressive move, the Court of Final Appeal ruled that same-sex couples are entitled to the same spousals visas as opposite-sex couples.

In November, an attempt to get the government to study policies affecting the LGBTQ community, and offer rights like the ability to make medical decisions for one's partner and the right to claim the body after death, was voted down 27-24.

People take part in the Lesbian, Gay, Bi-sexual and Transgender (LGBT) parade in Hong Kong on November 6, 2015.

That same month, a gay man named Nick Infinger lodged a judicial review against the Housing Authority for denying him public housing because he was married to a man.

People Power legislator Raymond Chan Chi-chuen, Hong Kong's only openly gay legislator, who put forward the aforementioned unsuccessful bill late last year, said he understood that some in the community were concerned that a failure to succeed in a same-sex marriage case could set the cause back. However, he reported being supportive of the efforts.

Justice Anderson Chow Ka-ming cleared both parties to go ahead with their cases, but put them on hold to first hear the case of a 29-year-old lesbian, known as MK, who is seeking a civil union partnership system in Hong Kong. He said that case would cover the issues related to those in the applications presented by both men.