A gay man has filed a lawsuit against a civil affairs bureau in Changsha, the capital of Central China's Hunan Province, for not accepting his marriage registration application, marking the nation's first case defending the marriage rights of same-sex couples.

Sun Wenlin (pseudonym) first applied for a marriage certificate for himself and his boyfriend on June 23 at the civil affairs bureau in the Furong district of Changsha after the couple had been dating for one year.

But his application was turned down by a bureau official, who said that only "one man and one woman" can be registered as married, according to Sun.

"The original text of the marriage law does not say one man and one woman, but a husband and a wife. I personally believe that this term refers not only to heterosexual couples but also to same-sex couples, to gay men and lesbians. The law is not discriminatory," Sun told the Global Times.

Sun filed the case in a local Furong district court on Wednesday, and the court should decide whether or not to accept the case within seven days.

Sun said that a court official also initially refused to accept his case documents, again saying that only a man and a woman can be married based on the marriage law. The official only "reluctantly" accepted the case after Sun threatened to file a complaint, and the official did not give Sun a written confirmation to prove that the case had been filed.

According to Shi Fulong, Sun's lawyer, that official's actions go against the new system of regulations to ease filing procedure launched by the Supreme People's Court on May 1, requiring courts to accept cases immediately as long as they meet certain basic requirements.