Christian financial advisers are calling for a "drastic" cap on the rates charged by payday loan companies.
The Association of Christian Financial Advisers (ACFA) said the loan charges, which can be at thousands of per cent, exploit the vulnerable and expose them to financial ruin.
It made the warning as the Government announced plans to give the Financial Conduct Authority powers to limit the charges.
ACFA spokesman Aidan Vaughan said the exorbitant interest rates were akin to "legal extortion".
He said he was delighted to see the Government taking action to protect the desperate and vulnerable from such charges.
"While there has to be personal responsibility in taking out loans, the feeding frenzy of greedy loan sharks has to be curtailed," he said.
"We believe all interest rates on personal loans should be limited by law."