A man molested his young nephew just two months after serving a sentence in a reformative training centre for outraging the modesty of another boy.

The 21-year-old man was sentenced yesterday to three years' jail and six strokes of the cane after pleading guilty to two counts of molestation. He cannot be named due to a gag order to protect his nephew's identity.

The court heard that the man was sentenced to reformative training in 2016 for molesting a nine-year-old boy in a lift.

Those sentenced to reformative training must spend between 18 months and three years in a reformative training centre. They must also follow a strict regimen that includes foot drills and counselling.

The man was released in March. Two months later, he targeted his sister's six-year-old son.

The boy's parents had left their Yishun flat on May 27 to collect some food, leaving the man, his mother and the child at home.

The boy was asleep on a mattress in the living room while his grandmother was in another room.

The court heard that the man then felt a desire to touch his nephew. He undressed the boy and outraged his modesty.

He was caught red-handed when the parents came home and saw their son half-naked. They confronted the man and the boy's father lodged a police report two days later.

Yesterday, Deputy Public Prosecutor Goh Yi Ling told District Judge Lim Tse Haw that an Institute of Mental Health report showed the man has a high risk of reoffending.

The man, who was unrepresented, told the court he would like to tell his sister that he was sorry for what he had done.

For each count of molestation, he could have been jailed for up to five years and fined or caned.