Fraud cases have risen by 16% with con artists stealing more than £3m a day, according to figures from the banking industry.
Criminals have particularly targeted victims by tricking them out of their one-time passcodes, trade body UK Finance said.
Despite the increase in reported cases, total losses have fallen slightly – totalling £572m in the first half of the year.
Banks said that fraud posed a “major threat” to the UK and called for support in tackling the crime.
The figures come after BBC Panorama revealed earlier this week a stream of cases involving e-money firm Revolut.
One victim told of how he lost £165,000 from his business account within an hour. Revolut said it had “robust controls” in place.
Changing tactics by fraudsters have seen cases rise in the first six months of this year, compared with the same period last year.
Unauthorised payments rose sharply, with losses up 5%, driven in part by fraudsters circumventing protection systems.
When a customer makes a payment online, they are often sent a one-time passcode to verify the transaction.
Fraudsters have found ways to trick people into telling them these codes, in order to steal money.
However, the latest data shows there were relatively large falls in romance and investment scams.
This may have been the result of the promise of stricter rules regarding so-called authorised push payment (APP) fraud prevention.
When criminals dupe their victims into sending them money by pretending to be a legitimate company, such as their bank or a tradesperson, or by selling goods that do not exist, this is known as APP fraud.
New mandatory rules took effect on 7 October which will see UK banks refund APP fraud victims up to £85,000 within five days.
Before the compulsory rules came in, most banks had signed up to a voluntary reimbursement code.
There were 97,344 cases of APP fraud in the first half of the year, with total losses of £214m.
“Fraud continues to pose a major threat in this country,” said Ben Donaldson, managing director of economic crime at UK Finance.
“In addition to the financial impact, this crime can cause severe psychological harm to victims.
“This isn’t a fight we will win alone.”
On Sunday, Charlie Nunn, chief executive of Lloyds Banking Group, accused Meta, the tech giant which owns social media platforms Facebook and Instagram, of “enabling” people to be contacted by fraudsters running online scams.
Meta said in response that its “pilot Fraud Intelligence Reciprocal Exchange programme (FIRE)” was designed to enable banks to “share information so we can work together to protect people using our respective services”.