SINGAPORE - A 29-year-old man who forced his wife to prostitute herself to pay for their baby son's diapers and milk powder, and sexually abused his daughter and niece failed in his appeal on Thursday (July 16) for a lighter sentence.

The man, who is unemployed, was sentenced to 25½ years' jail and 24 strokes of the cane last year by the High Court.

On Thursday, his lawyer, Mr Mohammad Shafiq Haja Maideen said the judge was wrong to allow his own disgust over the man's actions to influence his judgment on the appropriate sentence.

The lawyer argued that the judge was influenced by disgust because he described the man's actions as "monstrous" in his written judgment.

Mr Shafiq, who sought a sentence of 18 years' jail and 12 strokes of the cane, also argued that the offender had sexually assaulted his six-year-old daughter only once.

These arguments were rejected by a three-judge Court of Appeal, which said the sentence was not manifestly excessive.

Delivering the apex court's decision, Judge of Appeal Judith Prakash said the lawyer's criticism of the High Court judge was unwarranted.

"The judge's descriptions of the appellant's behaviour were reflective of general societal views on the responsibility of a father, husband and uncle towards his female relatives and were not exaggerated or extreme in any way," she said.

Justice Prakash said the man had abused the trust of his daughter - "even one instance is one too many", she said.

The offender, who cannot be named to protect the victims' identities, was described by prosecutors as a "monster".

He forced his wife to service three to five men a day for two months in 2016, making her hand over all her earnings to him.

He made her film the sexual acts, and inflicted physical and psychological abuse on her when she did not earn enough money or when he felt jealous of her customers.

Once, after having sex with his wife, he forced his daughter to perform oral sex on him.

On another occasion, he became angry with his wife for failing to service more customers and insisted that she bring her 13-year-old niece to him.

The woman eventually complied, even though she knew her niece was having her Primary School Leaving Examination that day.

She took her niece to a Balestier hotel, and left the room.

The man then pinned the girl to the bed, fondled her and placed a pillow over her face to muffle her screams.

When the girl stopped struggling, he ceased the assault and notified his wife, who later took the girl to a polyclinic.