The comments come following a BBC investigation that alleged some firms held on to clients' cash rather than paying it to creditors in a bid to secure lower settlements.
David Fisher, OFT director of consumer credit, said businesses that operated a full final settlement model had a responsibility to tell consumers what they were doing with their money.
"We would be very concerned should a business mislead consumers," he said. "This would call into question its fitness to operate.
"We have warned the industry that it needs to improve its business practices and in June 2011 we will publish further guidance setting out the standards we expect of businesses that we license."
The BBC alleges that in one case Bolton-based Global Debt Solutions offered to arrange a repayment plan for £40,000 of credit card debt and loans but did not pass the money paid over to creditors.
As a result the creditors took the couple who had used the firm’s services to court, resulting in county court judgements against them.
Global Debt Solutions, which became 3 Step Finance, has since been shut down by the Insolvency Service.
Another company, Apex Debt Counselling & Management, is also named in the investigation as having withheld money from creditors.
Industry guidelines state that any money taken from debtors should be passed on to creditors within five working days.
Lisa Colclough, national money advice policy and development manager at Citizens Advice (CA) that offers free debt advice to consumers, said that some firms offered a useful service that people were prepared to pay for but a lack of regulation provided a fertile breeding ground for rogue operators.
"We continue to see far too many people whose debt problems have been made much worse by the high fees and poor service of some debt management companies - including cases where money is not passed on to creditors," she said.
The CA is calling for the Consumer Credit Act and data protection legislation to be updated to tackle these problems and has made a super complaint to the OFT calling for a ban on cold calls and upfront fees. A response is expected from the OFT next week.