He had joined dating app Badoo to meet new people, but little did he expect he would end up becoming a near victim of a credit-for-sex scam.

Mr Harry Wong (not his real name), 22, had received a match request in July from a 23-year-old woman who claimed to be a foreigner studying at a local university.

He found her cute and decided to accept her request, Mr Wong told reporters last Friday.

About a week later, the woman called Qiao Er told him she needed to pay her school fees. "She said she could give me a massage at $100 for two hours, with 'special' services," recounted Mr Wong, who is doing part-time work while waiting to enter university.

He was sympathetic and eventually agreed to the arrangement. She told him to meet her at Block 355 Sembawang Way on Aug 2.

When Mr Wong arrived at the meeting point, he received a call from Qiao Er who asked him to transfer $100 via payment platform Alipay at the AXS machine at the block.

As Mr Wong was about to make the transfer, several police officers who were conducting public outreach on credit-for-sex scams approached him. After speaking to full-time police national serviceman Keenan Tham, Mr Wong realised he had almost been scammed.

Special Constable Corporal Tham, 22, told the media that he and his colleagues had noticed Mr Wong on the phone, logging on to Alipay at the machine nervously - typical indications of a victim of a credit-for-sex scam. The police officer had been conducting public outreach with Sergeant Jacob Koh, 27, police NSF Dalton Chee, 19, and two other operationally ready police national servicemen.

Later that day, Mr Wong received a threatening phone call from a man who claimed to be Qiao Er's manager. The man said he would harass Mr Wong's family if he did not transfer the money.

The police officers advised Mr Wong to ignore the phone call. He subsequently received a few missed calls from unknown numbers possibly linked to the suspected scammer, but the calls stopped after a few days.

Sergeant Koh said the typical modus operandi of credit-for-sex scams involves the transfer of credits through iTunes cards or Alipay.

"The amount may start off at $100 at first, but it will escalate. The scammers usually will give excuses to get you to transfer even more money," he added.

Mr Wong said: "Now that I think about it, I don't know what came over me. I don't earn a lot of money, yet I foolishly accepted the offer."