Singtel is warning the public to be wary of scam calls, saying that such calls have doubled from last year.

A Singtel spokesman said yesterday that its customers have received more than 5,000 calls so far this year, with callers impersonating Singtel customer and technical support officers. Of these, tech support scams about the termination of Singtel services were the most common, making up about 10 per cent of the scam calls, said Singtel.

The number reflects only scams that were reported to Singtel, the biggest mobile telco here, with about 50 per cent of the market share.

Among the other telcos, M1 said yesterday that although it does receive such reports from customers, the company has not seen a significant increase in cases year on year. However, it warned its customers to protect themselves by blocking unknown spam call numbers on their phones.

StarHub assistant vice-president for corporate communications Cassie Fong also said yesterday that the telco is aware of the rise in digital scams, which have become "very common in the digital age".

She urged customers to stay vigilant and be aware that such scams can come in many forms - e-mails, SMSes, tweets, Internet browser pop-ups and online ads.

To help its customers recognise the tell-tale signs of a scam, Singtel launched a "Jaga (guard) your data" scam awareness campaign yesterday. The campaign comprises three short films, each playing out a telco-related scam scenario.

Ms Lian Pek, vice-president of group strategic communications and brand at Singtel, said: "It's unfortunate that ongoing scams using the Singtel name or that of other companies have been so pervasive and that many people have become the targets of tricksters impersonating our technicians and customer service officers.

"By serving up anti-scam advice and lessons with a dash of humour with the aim of making the messages stick, we hope to foil some of these scammers' efforts by encouraging Singaporeans to stay vigilant to protect themselves and their families."

Separately, the Inland Revenue Authority of Singapore (Iras) warned the public to be wary of a scam e-mail, titled "Coronavirus Tax Relief and Economic Impact Payments".

The e-mail, purportedly sent by Iras, claims to offer a new Covid-19 tax relief for businesses and individuals affected by the pandemic.

Those who have responded and shared their personal or financial information with the senders are advised to lodge a police report.