Two lawsuits challenging Hong Kong's ban on same-sex marriage have been filed in the Chinese region.

According to the Thomson Reuters Foundation, plaintiffs in the cases are two men, an activist and a student, who argue that the ban violates the city's Basic Law, its regional constitution.

After a preliminary hearing held on Thursday, the Hong Kong High Court agreed to allow the cases to proceed.

“It is regrettable that further judicial cases need to be brought to force the government to end the discrimination same-sex couples face in all walks of life,” Amnesty International's Doriane Lau told Reuters.

Lau said that gay and lesbian couples are not eligible for public housing or to receive their partner's pension benefits.

Hong Kong, a former British colony, decriminalized gay sex in 1991. The region returned to Chinese control in 1997.

A 2017 University of Hong Kong survey found that a majority (50.4%) of respondents support same-sex marriage.