Consumers have just 10 weeks left to make a claim against their bank over the mis-selling of payment protection insurance (PPI), with experts predicting a late spike in complaints.
Figures published by the City watchdog, the Financial Conduct Authority (FCA), show that during April £334.3m was paid to customers who were wrongly sold the insurance.
This is higher than the £325.9m total payouts recorded during March.
PPI was sold alongside mortgages, credit cards and loans during the Nineties and 2000s and was intended to pay out in the event that the policyholder lost their job, became ill or died.
But few checks were made to ensure that customers were not already covered by other policies, leading to widespread mis-selling.
The FCA has imposed an August 29 deadline for any complaints to be made, despite billions of pounds remaining unclaimed and thousands of new victims coming forward each week.
The watchdog said its PPI claims website had been visited by 3.9 million users since launch. The total amount paid out by banks and credit card companies since January 2011 is £35.3bn.
Its high-profile advertising campaign featuring Hollywood actor Arnold Schwarzenegger has relaunched and will continue throughout the summer.
However, Steve Kitchen of Huntswood, an advisory firm, warned that any customer refund applications should be made well in advance of the deadline, as banks were expecting a deluge of complaints in August.