Nearly 6,000 people put in bogus compensation claims to the Financial Ombudsman last year, saying they had been mis-sold payment protection insurance (PPI).
The figures emerged as PPI drove a 28% increase in complaints to the ombudsman in the past financial year.
There were 157,716 gripes raised about PPI - a 51% rise on 2010-11.
Although unjustified complaints made up less than 4% of the total PPI figure, the number has raised concerns.
Claims management companies have been accused of exploiting the multi-billion pound payout of PPI compensation by banks.
However, the body that represents these claims companies - the Claims Standards Council - has previously said that many people cannot remember whether they had PPI policies year ago, and so these companies provide a service.
PPI was sold along with loans and credit cards, wrongly in many cases, to cover repayments if people became ill or lost their jobs.
Millions are being encouraged by claims companies to put in complaints about PPI cover. In the last financial year these firms initiated 69% of the PPI claims that went to the ombudsman.
This was a smaller percentage than the 76% they were responsible for in the previous year.
However, it is clear that among them are those who never had a policy.
The Ombudsman Service faced a fourfold increase in these groundless claims in 2011 to 5,661, the vast majority submitted by claims companies.
The cities with the highest number of bogus applications were Belfast, Birmingham and Sheffield, the ombudsman said.
"I think it is perfectly understandable for people to ask their bank - did I have PPI?," said Natalie Ceeney, the Chief Financial Ombudsman.
"At the same time we are seeing consumers being very badly misled by claims management companies."
Banks are in the process of paying out £9bn in compensation to borrowers who were mis-sold PPI, usually because they could never have claimed on the policies.
The huge payout has spawned an industry devoted to getting hold of a slice of the money.
Claims companies text or phone people encouraging them to claim, whether or not they were mis-sold a policy or even had one.
Then they charge consumers a fee of 25% of any payment, plus VAT.
"Some of them, at their worst, are taking upfront fees and the consumer is losing out," said Mrs Ceeney.
"They never had a policy and they are worse off than if they had done nothing."
Banks have complained about a cascade of spurious claims. Earlier this month Antonio Horta-Osorio, the chief executive of Lloyds Banking Group, said one in four claims his bank had received had come from people who had never had a PPI policy with the bank.
These latest figures show that some claims management companies are appealing to the ombudsman, even though a complaint has already been rejected by a bank on the grounds that there never was a policy.
The Ombudsman Service has faced a deluge of PPI complaints. It made up 60% of the 264,000 claims total. Some 64% of these claims were upheld, compared with 51% previously.
The service is taking on 500 extra staff to process them.
It said that bogus claims clogged up the works and delayed compensation payments to the majority of deserving cases.
Other types of financial service also provoked noticeable increases in complaints to the ombudsman.
Insurance complaints, apart from PPI, rose by 31%, those about credit cards by 10% and ones about mortgages by 35%.
However complaints about banking and loans were down by 1%.
The service is the next stage for complainants who are not satisfied when they make a complaint to a financial services company.
It has the power to award compensation if a customer has been treated unfairly.