A Japanese expat trespassed into a women's toilet at Far East Square and molested a woman as she was washing her hands.

Warehouse manager Wataru Murase, 29, did not run away when his terrified 21-year-old victim screamed.

When she moved into a squatting position to protect herself, he did the same and tried to touch her again before fleeing the scene.

Murase pleaded guilty in court yesterday to two counts of criminal trespass and one of molestation. Two other criminal trespass charges will be considered during sentencing.

The incident happened at 11.43pm on Oct 12 last year when he entered a toilet for women on the first storey of Far East Square in Pekin Street, but was chased out by an unknown woman.

He headed towards a nearby men's toilet and lingered in the vicinity before returning when the woman left the premises.

But when his 21-year-old victim entered the same women's toilet shortly after midnight, he ran inside.

Deputy Public Prosecutor Amanda Han told District Judge Kenneth Yap that Murase approached his victim from behind and slipped his hands into her top.

The DPP added: "The victim immediately covered her chest, squatting down to protect herself while screaming. However, the accused persisted and squatted down as well... Eventually, the accused gave up and ran out of the toilet."

The woman went out a few seconds later and approached a nearby security guard, who advised her to alert the police.

The court heard that the victim made a police report later that evening. Murase is now out on bail of $10,000 and is expected to be sentenced on Nov 26.

For outraging the woman's modesty, he can be jailed for up to two years and fined or caned.

And for each count of criminal trespass, he can be jailed for up to three months and fined up to $1,500.