Fraudsters' takeovers of customer accounts has soared by 45% in the last year, according to figures.
The number of so-called facility takeovers, when a fraudster poses as a genuine customer to gain control of an account, rose to 22,525 in the UK in 2016, up from 15,497, analysis of more than 325,000 recorded cases by fraud prevention service Cifas found.
Victims often find money has been transferred out of their account or products have been ordered in their name.
For the fraud to be successful over the telephone, criminals must have obtained enough of their victim's personal and security information to convince a call centre worker they are the account holder.
Any account can be taken over by fraudsters, including bank, credit card, telephone, email and other services, Cifas warned.
More than 50% of the facility takeovers recorded were carried out over the phone, typically to call centre staff.
The data, from 387 organisations including many major UK brands, found that identity crime and facility takeover remains the biggest threat, making up 60% of fraud.
Some 88% of identity fraud was carried out online, compared with 30% of facility takeovers, the annual report found.
Cifas said the increase in facility takeovers was a sign that criminals were fooling individuals into revealing personal details in response to increased security for customer accounts.
It said fraudsters were collecting personal information and identifying targets through data breaches and social media footprints, and were often contacting victims directly to manipulate them into revealing further details.
Cifas chief executive Simon Dukes said: "Working together, organisations prevented £1 billion worth of fraud last year, but we know that as one method gets harder, fraudsters change tactic rather than stop.
"We are now seeing that the advances made in securing online access to customer accounts have led to fraudsters targeting the human being at the end of the phone.
"Using old-fashioned but highly effective con artistry, they are tricking individuals into giving away their personal details and deceiving call centre staff into making transactions on their victims' accounts. The proliferation of personal data that is available either online or through data breaches only makes this easier.
He added: "When people are targeted, education is key and we urge the next government to do more to ensure that individuals know how to avoid these tricks and can recognise the signs of a scam.
"Organisations, too, must focus on education for call centre staff and ensure they make the most out of new fraud prevention technology."
Alex Neill, Which? managing director of home products and services, said: "Educating consumers is not the only solution. There's only so much people can do to protect themselves as sophisticated fraudsters are constantly finding new tactics to persuade them to part with their money.
"Banks and businesses should be doing more to identify potential scams, and ensure that their security systems are being improved to prevent fraud taking place.
"The next government needs to commit to an ambitious agenda for tackling fraud, with action to improve how customer data is kept safe and ensure that financial institutions do more to protect consumers from scams."