SINGAPORE - A 48-year-old chief executive, who is awaiting judgment for allegedly sexually assaulting his son's nine-year-old classmate during a sleepover in 2015, has been charged with sexually abusing another boy in 2011.

Five fresh charges were brought against the foreign national on Wednesday (Aug 1). He cannot be named to protect the identity of the boys.

The new charges relate to a string of sexual offences against an eight-year-old boy which were committed at the home of the accused between April and May 2011.

He faces one count of attempted sexual assault by penetration for trying to perform oral sex on the boy, three counts of molestation for touching the boy's genitals and one count of showing a pornographic video to the boy.

Separately, the High Court is expected to deliver its verdict next Monday on the first set of charges relating to the nine-year-old boy.

The accused, a father of three boys, had claimed trial to one count of molestation and two counts of aggravated sexual assault by penetration.

The nine-year-old, a classmate of his youngest son, was one of the children who were invited by the accused and his wife for a Halloween trick-or-treat party, followed by a sleepover, on Oct 31, 2015.

The boy slept on the upper deck of a bunk bed while the son slept on the lower deck.

During the trial, the boy testified that later that night, he pretended to be asleep when he saw the accused entering the room. The man stepped on the lower bunk and touched his genitalia, said the boy.

The boy said the man left the room but returned shortly after to perform oral sex on him.

After the man left the room for the third time, the boy decided he did not want to stay any longer.

The boy packed his belongings and went to the bedroom of the accused to tell him that he wanted to go home as he was feeling unwell. The wife of the accused then contacted the boy's father to pick him up.

After getting into his father's car, the boy told him what the accused had done to him.

The accused denied the allegations.

Among other things, he suggested that the "scary" atmosphere of Halloween caused the boy to imagine the sexual acts and that the boy's complaint was "attention-seeking behaviour".

The punishment for aggravated sexual assault by penetration is a jail term of between eight and 20 years, and at least 12 strokes of the cane.