Many consumers believe that firms offering financial products such as mortgages, bank accounts and credit cards use separate fees or charges to "trick" them into thinking the cost is lower than it really is, according to research by Which?

Two-thirds (68%) of people surveyed by the consumer group who have paid a charge for a financial service or product in the last year agree that companies make costs more complicated to cause confusion and only one in five (19%) think charges are representative of firms' actual costs.

Which? has launched a "stop sneaky fees and charges" campaign, which is calling for all financial fees and charges, including those on insurance policies, mortgages, bank accounts and credit cards, to be shown upfront so that people can shop around more easily and compare overall costs.

More than 2,000 people were surveyed for the Which? research, of which just under half had paid a fee or a charge on one of these financial products in the last 12 months.

Six in 10 (62%) people agreed it is difficult to compare the total cost of financial products and services as fees and charges vary so much.

A separate Which? investigation into the car insurance market found that despite premiums being generally on a downward path, fees have been on the rise.

Of 28 car insurance companies looked at by Which?, some had doubled or even, in one case, tripled their cancellation charges since similar research was carried out three years ago.

Eight companies had also introduced new fees and charges, with some demanding set-up fees of £20 for a policy or charging for duplicate documents if customers want to receive them in the post.

Which? is urging the Government and the regulator to conduct a review of financial fees and charges across the board "to make sure the price you see is always the price you pay".

It said that, for example, credit card providers should stop advertising balance transfer deals as "0%" when a balance transfer fee applies and instead they should be prominently displaying the level of the fee.

Richard Lloyd, executive director of Which?, said: "Consumers are fed up with being hit with unexpected, additional costs for financial products that lead to them paying more than they bargained for.

"These fees can be hard to avoid, and people often don't know what they're really paying for.

"We want the financial services industry to stop sneaky fees and charges, and put an end to excessive, unclear and hard to compare fees that do nothing to improve the low level of trust in these markets."

Hugh Savill, the Association of British Insurers' (ABI) director of regulation, said: "Insurers are not interested in hiding any charges from their customers and follow regulatory requirements so that any additional charges are clearly set out.

"Insurers have also recently written to the regulator asking for reforms to ensure more customer-friendly information on renewal pricing.

"The motor insurance market is very competitive, with the average private motor insurance premium having fallen by 14% since the start of 2012.

"Insurers agree that it is important customers are fully aware of any administration and cancellation charges when comparing premiums and the cover offered by providers, and this is a responsibility for all those who sell insurance, including comparison websites and brokers as well as the insurers themselves."

The ABI said i nsurers, intermediaries and price comparison websites are required by industry regulator the Financial Conduct Authority (FCA) to clearly set out to the customer before and after the contract is agreed, in addition to the premium, other charges that could arise such as administration costs for policy alterations and cancellation charges.

The ABI has recently proposed an initiative that would ensure that all motor and home renewal documents include the premium that the customer started the year paying alongside the renewal quote, for easy comparison.