A former safety supervisor who molested a young teenage boy 11 months into a conditional warning for a similar charge was jailed for 30 months and ordered to be given three strokes of the cane on Tuesday.

Paul Tan Weixiang, 33, unemployed, had been given a 12-month conditional warning for groping a 14-year-old in 2012 but he breached it on March 28 last year when he touched the second teen, aged 13, at a shelter near Block 417 Jurong West Street 42.

He was fined $3,000 for having obscene films in his mobile phone at his home in Bukit Panjang on April 9 last year. He had pleaded guilty to the three charges.

Deputy Public Prosecutor Kenneth Chin said the 13-year-old came to know Tan sometime in March last year while they were playing basketball at a community club.

A few days later, the teen received a text message from an unknown phone which he later found out was Tan's. The teen received greeting messages over the next few days but did not reply to them.

On March 28, the victim sent a message to Tan to ask if he knew a friend he was looking for. The victim needed to find this friend to retrieve a basketball, without which he would have to compensate his classmate $50.

Tan then volunteered to pay the money for the victim who then agreed to meet Tan that evening at a shelter in Jurong West where the offences were committed.

Before Tan let him go, he passed the teen $50 to repay his classmate. The victim took the money and ran back home. He told his parents about the incident and subsequently lodged a police report.

In the 2012 case, the court heard that Tan and the 14-year-old victim were known to each other as they used to play basketball together.

Tan met the victim on April 1 that year and bought him a drink. They started chatting and Tan suddenly touched the teen. Police arrested Tan following a tip-off from an unknown caller who reported a case of "inappropriate'' touching.

Mr Chin told the court a psychiatric report showed that Tan had been "grooming'' males aged between 14 and 20 years old for almost 10 years to establish closer relationships with his younger friends for furthering the sexual acts.

Tan, he added, failed to appreciate the second chance given to him and breached his 12-month conditional warning by molesting the 14-year-old twice on March 28.

Tan could have been jailed for between two and five years, fined, caned or given any combination of the punishments for the molestation charges.