SINGAPORE - A man who was originally given a mandatory treatment order (MTO) for trespassing into female toilets and peeping at women was jailed for two months and two weeks on Friday.

Lim Keng Siong, 29, had admitted to six of 37 charges of insulting modesty and criminal trespass in October 2013. He was given 24 months' MTO, which entails psychiatric treatment in lieu of jail time.

The prosecution appealed.

In April last year, the High Court set aside the MTO and ordered further evidence to be taken as to the nature of Lim's condition of voyeurism.

Barely a month after Lim was out on bail, he re-offended. The court heard he entered a female toilet at Singapore Polytechnic on May 12 last year, and tried to peep at an 18-year-old student in the toilet cubicle.

The victim was using the squat toilet when she saw a pair of hands on the floor of the adjoining cubicle. She left and told two of her friends what happened.

When Lim came out, the victim and her friend followed him. He apologised repeatedly. Security was alerted and the police called.

In November last year, Lim admitted to the two fresh offences during a Newton hearing where psychiatrists testified on voyeurism and Lim's mental condition.

On Friday, District Judge Shaiffudin Saruwan accepted Institute of Mental Health consultant psychiatrist Stephen Phang's evidence that voyeurism is not an impulse-control disorder.

Dr Phang said it is a "sexual deviancy", because the individual always has an "unfettered choice" to decide whether to indulge in such behaviour or not.

In the earlier set of offences, Lim was studying at SIM University when he committed offences at Jurong Gateway Road and SIM University at Clement Road.

He had used his mobile phone to record a 28-year-old housewife relieving herself in the Jurong Gateway Road toilet on Oct 15, 2012.

Earlier in August 2011, he went into the female toilet at SIM University and "camped" inside, "smelling the air". Subsequently, he extended a video camera from under the cubicle to the next cubicle to intrude into the privacy of a 21-year-old.

She shouted, came out and hammered on the door of the cubicle. Shortly after, Lim opened the door and tried to dash out but she detained him.

The maximum penalty for intruding into the privacy of a woman is one year's jail and a fine.