Debt counselling service Citizens Advice has lodged a "super complaint" to the Office of Fair Trading requesting a probe into the sale of PPI, in particular sales made with credit agreements.

It claimed too many consumers are paying too much for cover or could not claim on the policies they had been sold.

Citizens Advice said new regulations had failed to protect consumers, despite the FSA taking over regulation of the market in January.

The OFT website confirmed that the department will fast-track the complaint and will announce what action it proposes to take in the 90 days.

David Harker, chief executive of Citizens Advice, said: "We first reported these problems 10 years ago. It is a scandal that in this time so little has been done to remedy them.

"We badly need an official investigation of how this market is operating, leading to effective regulation that ensures a fair deal for all consumers and protects the most vulnerable."

Although the FSA launched an inquiry into PPI in May, it is not focusing on price-related issues because it is not within its regulatory remit. Citizens Advice is hoping that by launching the super complaint, regulators will be forced into action.

Robin Gordon-Walker, FSA spokesman, defended its actions saying: "We have made this a high priority and identified PPI as an area of risk. But it would be wrong to rush into this without getting the right evidence, especially if it may result in enforcement action."

The FSA probe, which is in its final stages, will focus on claims of hard-selling tactics, whether the products sold suited the consumer and whether exclusions to the cover were being clearly pointed out.