A senior immigration officer in Hong Kong has claimed that decisions by the heads of the Civil Service Bureau and Inland Revenue discriminated against his sexual orientation and were unconstitutional.

The case centres on the government's failure to offer equal rights to same-sex married couples as heterosexual couples.

Leung Chun-kwong was married to Scott Paul Adams in 2014 in New Zealand. After reporting this to the Civil Service Bureau he was informed that "the voluntary union for life of one man and one woman" and it "falls outside the meaning of marriage."

Leung again contacted the bureau and also the tax department to change his legal marital status to married in order to seek a join assessment with his spouse. The tax department refused to recognise his marriage.

Leung therefore applied to the High Court claiming that the government's insistence that marriage could only be between one man and one woman discriminated against his sexual orientation. He also found it was against Hong Kong's Bill of Rights, which says all residents are equal.

His application document states: "At its heart, this matter concerns protection for the dignity of a historically oppressed class in our society – homosexual persons, a substantial portion of our society. Allowing discriminatory treatment against such a minority undermines the law."