The Attorney-General's Chambers on Thursday put forward several arguments for keeping a law which criminalises sex between men, in its defence against a challenge from a gay couple.

The case was heard in chambers by Justice Quentin Loh, after graphic designers Gary Lim and Kenneth Chee sought a repeal of Section 377A, arguing that it goes against Article 12 of the constitution which says all persons are equal before the law.

But among other things, the AGC submits that Section 377A has the "clearly-stated purpose" of reflecting public morality.

"This is based on the fact that the majority of Singaporeans still find homosexual acts unacceptable, as reflected in parliamentary debates," it said.

"Although Parliament has chosen to retain the wording of Section 377A which does not encompass homosexual acts between females, this decision strikes a legitimate balance between the moral norms of the majority and the interests of homosexuals."

The gay couple's lawyers, Peter Low and Choo Zheng Xi, called the law "absurd, arbitrary and unreasonable". They also argued that the law causes harm to gay and bisexual men as it limits HIV/Aids outreach to them and causes them psychological damage.

Justice Loh has reserved judgment. Mr Lim and Mr Chee's challenge of Section 377A is one of two before the courts. The other is being mounted by Mr Tan Eng Hong, who is represented by lawyer M. Ravi.