The Presbyterian Church of Wales has called for government action on payday lenders.
The loans are taken out by people who need a cash injection to tide them over until the end of the month but they often come with extremely high interest rates.
The Church is concerned that the poor state of the UK economy is driving more people to take out payday loans.
Some banks and lenders are acting "inscrupulously" by refusing to lend to individuals and small businesses at reasonable rates, the Church said.
It also criticised the use of emotive adverts encouraging people to take out loans at certain times, such as Christmas.
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"Wonga.com is the best-known name in this sector, but there are dozens of other companies offering terrifically expensive short-term loans,”" said Rev Bryn Williams, General Secretary. “
"In some cases, the interest rate on a loan can be as high as 4,000 or 5,000%. Even though the companies argue that they only provide short-term loans, some people have to approach another company for a loan to pay off the first, and this results in even more debt. It'’s a vicious circle."
The Church has written to the Office of Fair Trading requesting that it reconsider its decision not to cap the interest rate.
It is encouraging member churches to offer practical help such as that provided by Noddfa Church, in Caernarfon, which is teaching locals how to budget and manage their finances.