She was only 12 years old when her stepfather first sexually abused her, with the 41-year-old going on to assault the girl on multiple occasions in 2017 and 2018.

He took advantage of her while they were alone at home or when the rest of the family were asleep, growing more intrusive with each act as he progressed from molestation to sexually penetrating her with his hand.

The abuse ended only when he was arrested, after the girl told a school counsellor.

The man was yesterday sentenced to 20 years' jail and 24 strokes of the cane after he pleaded guilty to two charges of sexual assault involving penetration.

Three other counts of outraging the girl's modesty and two other charges of sexual assault were taken into consideration during sentencing by Justice Dedar Singh Gill.

The girl and the man cannot be identified due to a gag order to protect her identity.

Court documents state that the girl was found to have mild intellectual disability, dyslexia and low cognitive abilities.

At the time of the offences, the man was living in a flat with the girl, her biological mother, grandmother and younger sister, as well as a domestic helper and a female tenant.

He had married the girl's mother in 2012.

The man started sexually assaulting his stepdaughter some time in July or August 2017.

He continued to abuse the girl over the next 15 months, committing the offences in the master bedroom with the door shut.

This included sexually penetrating the girl with his hand in October 2017 and in November 2018, when she tried to stop the man.

The girl did not confide in her family, afraid of how her mother and grandmother would respond and worried she may be disbelieved. She also did not want to further burden her mother, who had health issues.

But she eventually told her school counsellor on Nov 2, 2018 that the man "was doing things to her", and filed a police report. The man was arrested on the same day.

Urging the court to sentence the man to at least 20 years' jail and 24 strokes of the cane, Deputy Public Prosecutors Sruthi Boppana and Grace Teo noted that he had abused the girl within the sanctity of the family home, where she was entitled to feel safe and seek refuge.

In mitigation, defence lawyer Jonathan Wong said that his client wanted to reconcile with his family.

The man's jail term has been backdated to Nov 3, 2018, when he was first remanded.

For each offence of sexual assault involving penetration, the man could have been jailed for between eight and 20 years and punished with at least 12 strokes of the cane.