SINGAPORE - A domestic worker ironing clothes one afternoon had a shock when a drunk man trespassed into her employer's flat through the unlocked front door and crept into her room, the High Court heard on Thursday (Jan 9).

Mark Kalaivanan Tamilarasan, 40, allegedly told the 32-year-old woman that he was a police officer. He is said to have molested her and forced her to perform oral sex on him.

He is contesting four charges - one each of aggravated sexual assault by penetration, house-trespass, outrage of modesty and impersonating a public servant - in a trial scheduled for six days.

The court heard that he will be raising the defence of consent.

Deputy Public Prosecutor Chew Xin Ying told the court that the accused is likely to argue that the maid had led him to the flat, where she became intimate with him and willingly performed the sex act on him.

But the DPP said: "The prosecution will lead evidence to show that these are complete lies."

She noted that the accused was captured on police camera at the block of flats taking the lift up to the 15th floor alone.

Kalaivanan allegedly talked to at least one other maid and her employer through their door, pretending to be an immigration officer, before he chanced on an unlocked door.

The maid cannot be named under a gag order to protect her identity.

In her opening address, the DPP told the court that on July 15, 2017, after a drinking session with friends, Kalaivanan trespassed into the flat at about 3.45pm and entered the maid's room without any warning.

The only other person at home was the employer's bedridden mother, who was in the next room.

The DPP said the accused lied to the maid that he was a police officer and demanded that she hand over her passport, work permit and money.

When she did not comply, he grabbed her breast and touched her thigh. She begged him to stop but he threatened to beat her up, said the DPP.

As she repeatedly shouted "Tolong, tolong!", he pulled her to the kitchen toilet and told her to sit on the toilet bowl. He then forced her to perform oral sex on him.

Meanwhile, neighbours who heard her shouts for help called the police.

When she heard footsteps outside, the maid managed to escape and ran towards two police officers who arrived at the flat in response to the calls.