The government is considering appealing against a court decision to strike down a law prohibiting people from using public toilets designated for the opposite sex, saying the purpose of having gender-specific lavatories is to protect the privacy and safety of individuals.

The statement from the Environment and Ecology Bureau on Thursday came a day after the High Court ruled in favour of a transgender man who challenged the Public Conveniences (Conduct and Behaviour) Regulation.

But the court suspended the judgement for a year to allow the government time to come up with an approach.

The regulation bans people aged five or above from public lavatories managed by the Food and Environmental Hygiene Department allocated to their opposite sex.

The bureau said it is "carefully studying the judgment and seeking legal advice, and is considering lodging an appeal".

It also called on members of the public to continue to enter public toilets "according to the principle of segregation of the sexes" to avoid running afoul of the law.

"The establishment of sex-segregated public toilets under the Public Conveniences (Conduct and Behaviour) Regulation aims to protect the privacy and safety of the public when using public toilets, and to reflect social norms and expectations," a bureau spokesperson said.

"This arrangement has been widely accepted by society."

The government went on to say there were gender-neutral toilets available near about half of the sex-segregated lavatories that can be used by everyone, including transgender individuals.