The police are investigating 31 people over scams involving the impersonation of Chinese officials that caused victims to lose more than $6.9 million.

The police said in a statement yesterday that since last month, they had received several reports from victims saying they had received phone calls that were purportedly from banks or the police in China.

Impersonating Chinese officials, the scammers would tell victims that their credit or debit card details had been used for fraudulent transactions or that their bank accounts were involved in money laundering activities.

The victims, who were then told to transfer their money for investigations, handed over either their banking credentials or cash to money mules.

Most of them transferred money to bank accounts provided by scammers.

The amounts transferred or handed over ranged from $5,000 to $824,500. At least $6.92 million was lost in total.

Three of the suspects - a 19-year-old woman and two men, aged 22 and 62 - were arrested between March 22 and April 12.

They allegedly acted on the instructions of the scammers to meet the victims to collect cash or Internet banking tokens.

They allegedly showed the victims fake "China International Police" passes when they met.

Sometimes, the suspects would hand "official investigation documents" to the victims to create the impression that they were being investigated by the police in China.

The remaining 28 suspects, aged between 21 and 56, allegedly acted as money mules.

The offence of cheating carries a prison term of up to 10 years and a fine, and the offence of cheating by impersonation carries a prison term of up to five years and/or a fine.

The police said no government agency would request, over the phone, personal details, bank account log-in credentials or the transfer of money.

They advised members of the public to call a trusted friend or talk to a relative before they act, as they may be overwhelmed by emotion and make the wrong decision.

Scammers may also use caller ID spoofing technology to mask the actual phone number they are using and display a local one.

The police also warned against giving personal information such as identification card numbers, bank details, credit card details and one-time passwords to anyone.

Those who have information about such scams can call the police hotline on 1800-255-0000 or submit the information online at www.police.gov.sg/iwitness

For scam-related advice, the public can call the anti-scam helpline on 1800-722-6688 or visit www.scamalert.sg