A married construction worker has been jailed for more than six years after carrying out a non-consensual sexual act on another man at their dormitory in Jurong.

The two men did not know each other before the incident.

Indian national Paruppa Kownder Kulanthai, 51, pleaded guilty to one count of performing the sexual act without his victim's consent.

Paruppa, who has a wife and daughter back home in India, returned to the dormitory at around 10pm on Oct 7, 2017 after a drinking session and spotted the 29-year-old man sleeping near a staircase landing.

He went over and stroked the man's groin. He then pulled down the victim's trousers and started to perform oral sex on him.

The victim, an Indian national who cannot be named due to a gag order, woke up and saw that his private parts were exposed.

He punched Paruppa's face and the older man ran away.

The victim told a security officer about the incident and the police were alerted.

Deputy Public Prosecutor Thiagesh Sukumaran told the court: "The accused admitted that he was overcome with temptation when he saw the victim sleeping near the staircase landing (and) that he was drunk at the... time."

Paruppa, who was sentenced to six years and six weeks' jail by District Judge Shawn Ho yesterday, was not the first person imprisoned in recent weeks over such an offence.

Chalermnarong Namsri, 46, a tour coordinator, was sentenced to 5½ years' jail and three strokes of the cane on March 3 after pleading guilty to one count of carrying out a sexual act on a 24-year-old man without his consent.

The two Thai men had shared the same room at the Hotel Grand Central in Cavenagh Road last March when Namsri performed oral sex on his victim, who was asleep at the time.

Offenders who commit non-consensual sexual acts can be jailed for up to 20 years and fined or caned.

Paruppa cannot be caned as he is over 50 years old.