A kitchen helper who followed one woman into her flat and later molested another was jailed for 21 months on Wednesday.

Ong Bun Hock, 44, who wanted to befriend the women as he found them attractive, admitted to trespassing into the home of a Filipina, 27, and touching another woman, 24, in a lift in Yishun Street 11 on March 22 this year.

A district court heard that Ong had finished drinking at a coffeeshop at about 7am that day when he noticed the Filipino national walking nearby and decided to follow her.

After watching her for about 20 minutes, he saw her enter a ground floor unit at Yishun Street 22. He pushed her on the back, causing her to almost fall.

He asked her where her room was. The victim used her shoes to push him away and shouted. Ong took to his heels.

At about 9.15am, he saw another woman, the 24-year-old, walking to her block in Yishun Street 11 and followed her into the lift. Inside the lift, he touched her near her groin and said there was a hole in her shorts. She looked down and said there wasn't any hole.

He did not get out on the eighth floor though he had pressed the button for the floor but waited for the door to close before asking about her parentage. He pressed the 11th floor button.

Feeling suspicious, she made a phone call to her husband. When she walked out on the 10th floor, Ong touched her buttocks and commented that she was pretty.

A third charge of insulting modesty was considered.

Ong has previous convictions for theft, drug-related offences, robbery and trespass.