More than $7 million has been lost to scammers posing as technical support staff in the first four months of this year, an increase of more than 40 times from the same period last year.
The scammers deceive victims into believing their Internet connections have been compromised.
Victims lost some $3.2 million in April alone, when circuit breaker measures were in full force and more people were working or learning from home.
One victim was cheated of $958,500, the highest sum lost in a single case from January to April.
Similar scams had defrauded people of $169,600 from January to April last year, said the police yesterday.
Around 70 per cent of victims were aged 40 to 75, said the police, adding that scammers typically persuade their victims to install software applications like TeamViewer or AnyDesk, under the pretext that this would solve the connection problems.
But once the applications are installed, the scammers would have remote access to the victims' computers and can transfer money out of their bank accounts.
Some fraudsters use a similar tactic by pretending to be with the "Cyber Crime Department of Singapore" or the "Cyber Police of Singapore" - both of which are non-existent organisations.
Victims are told that they have "committed an offence", and must download the applications to help in investigations, said the police.
Criminologist Olivia Choy from Nanyang Technological University said there is a greater chance of people becoming victims when they are often with their devices, and this has been more pronounced as people rely even more on devices to communicate with others during the circuit breaker.
"We are all on our devices these days - that's how the majority of people are communicating with one another. So these problems are going to be more prominent and significant," she said.
Victims said scammers are often very convincing, and are quick to "verify" their own identities and allay further concerns.
A 61-year-old Singapore permanent resident, who wanted to be known only as Bavara, was contacted by a man purporting to be from Singtel in mid-April, a week into the circuit breaker period.
The highest sum a victim was cheated out of in a single case from January to April.
Ages of 70 per cent of the victims who fell for the tech support scams.
What victims of the tech support scams lost in April alone during the circuit breaker period.
Surge in the amount lost to such scammers in January to April from the same period a year ago.
Without prompting, the man offered his name, his "employee ID" number and a telephone number, before informing Ms Bavara that her IP address had been compromised, she said.
The man then referred her to another person, who claimed to be with the Cyber Security Agency of Singapore. They needed her assistance in tracking down hackers, she was told.
At their behest, she downloaded the TeamViewer app, and they told her that they needed to make a "fake transaction" with her bank account to track down the hackers.
When she raised concerns, they reassured her that she would be reimbursed, even producing a letter of authorisation from her bank, she said.
"The impersonator was very confident, polite, knowledgeable. I asked all kinds of questions and he had good answers to everything," said Ms Bavara, who runs a business development consultancy service.
"I was pretty much overwhelmed with all the details," she said, adding that the circuit breaker had added to her anxiety.
The scammers attempted to siphon off $170,000. Fortunately, her bank spotted something fishy and stopped some of the transactions, she said.
Ms Bavara realised she had been tricked only when the police called her to find out more about the suspicious transactions flagged by the bank. In the end, she was swindled out of around $94,000, as some transactions were not stopped in time.
"I'm not an expert doubter... that's probably why I paid for it with this kind of experience," she said, adding that she will double-check the identities of unknown callers in future.