Some banks are pressuring customers with debt problems to take out new loans, a consumer group claimed.
Debtors who have problems servicing their existing loans are being targeted by aggressive phone sales from some banks, the Citizens Advice Bureau warned.
A spokesman said some banks were encouraging people with loan difficulties to either pay back what they owed or take on extra, more expensive debt.
"Banks are still pressuring people with phone calls," a spokeswoman said. "They want them to either pay back what they owe or take out extra credit.
"People who shouldn't be taking on more debt are getting pestering letters and phone calls," she warned.
The CAB has urged regulators and banks to take action to stop irresponsible lending.
It helps borrowers in trouble by negotiating with banks on their behalf.
The number of debt problems it handled last year increased by 20% to 1.7 million, setting a new record.
The group said it was working hard to help people tackle their debt problems, and was also developing new services to help prevent debt, such as providing advice on financial planning and improving people's money management skills.
