A man who helped his friend deal with a problem involving a former mistress ended up cheating him of more than $30,000 for the maintenance of a fictitious child.

Singaporean Ho Chee Wai, 34, even created fake Facebook accounts and recruited another friend for the ruse to convince the victim that he had fathered a child with the Vietnamese woman.

For the scam that stretched over nine months, the interior designer was sentenced to 14 weeks' jail yesterday.

The court heard that it started when Ho's friend, Mr Soo Guo Woei, became intimate with a KTV hostess known only as Ms Ah Thao after meeting her at a pub in 2011.

The affair, which lasted about two months, ended soon after she returned to Vietnam when her work permit expired.

Shortly after she returned home, she informed Mr Soo that she might have become pregnant with his child.

Unsure of what to do, Mr Soo, a retail executive, sought the advice of Ho, who told him to ask Ms Ah Thao to go for an abortion. After the incident, he stopped communicating with her.

About three years later in 2014, Ho hatched a plan to cheat Mr Soo.

He roped in another friend, Chua Rui Xiang, who pretended to be Ms Ah Thao's boyfriend.

Posing as Ah Xing, Chua demanded payments for the maintenance of her "child" fathered by Mr Soo.

He also threatened to send photographs of Mr Soo and Ms Ah Thao as well as the "child" to Mr Soo's wife.

To convince Mr Soo that the woman was indeed seeking maintenance through her new beau, Ho created three fake Facebook accounts for Ah Xing, Ms Ah Thao and the fictitious child.

In February 2014, Mr Soo complied and made several transfers to Chua's bank account. The latter split the money with Ho.

Oblivious that Ho was the mastermind, Mr Soo confided in his friend again and sought his help to liaise with Ms Ah Thao's "boyfriend" later that month.

From then on, Ho would inform Mr Soo of the amount he needed to pay for the maintenance of the fictitious child. Mr Soo would then transfer the money to Ho's bank account or pass him cash and other valuables.

The scheme finally unravelled after about nine months, when Mr Soo made a police report in November 2014.

Yesterday, District Judge Marvin Bay said the case represents a "truly brazen and cynical exploitation" by Ho of his friend's situation and desire to "do the right thing" to support the imaginary child.

Ho made full restitution of the $30,900 cheated to Mr Soo in February last year.

Correction note: In a previous version of this article, it was reported that Ho was sentenced to 14 months' jail. He was sentenced to 14 weeks' jail. We are sorry for the error.