Rights activists in Hong Kong celebrated a landmark victory against government policy that entitles a gay civil servant's husband to the same benefits as heterosexual colleagues' spouses.

The court on Friday rejected the Civil Service Bureau's claim that granting benefits would damage "the integrity of the institution of marriage."

Senior immigration official Leung Chun-kwong bought the challenge last year, claiming that the civil service and the Inland Revenue Department should recognise his union to Scott Adams who he married in New Zealand.

Mr Justice Anderson Chow Ka-ming labelled the bureau's policy "indirect discrimination" though did not rule in favour of Mr Leung when it came to his tax affairs.

In his ruling, Mr Chow wrote "I am unable to see how denial of 'spousal' benefits to homosexual couples ... legally married under foreign laws could or would serve the purpose of not undermining the integrity of the institution of marriage in Hong Kong."

Mr Leung applauded the decision and said "we simply wanted to be treated fairly and with dignity."

"The government is the biggest employer, the whole of Hong Kong will follow [the decision]," he said according to the South China Morning Post.

The ruling could have an immediate impact on gay couples employed in the Hong Kong civil service and the bureau sad it would be examining the ruling in detail.

Mr Leung encouraged the government to take this opportunity to review discriminatory policies.