Consumers are being alerted by the Money Advice Service and Financial Fraud Action UK (FFA UK) to new telephone scams in which fraudsters try to obtain individuals' bank and credit card details or intercept legitimate transactions being made by diners in restaurants.

The Money Advice Service has warned that people are being contacted by fraudsters pretending to be working on its behalf and typically offering advice on debt or pensions. The service says it never cold calls individuals, and would not ask for bank details or help with transferring a pension, credit card or bank account. It offers advice and guidance on handling financial affairs but does not do so directly for individuals.

Meanwhile, restaurant owners and diners in London and the south-east are being warned by FFA UK to stay vigilant as fraudsters attempt to target them in a new scam.

Criminals posing as bank staff are telephoning restaurants claiming there is a problem with the restaurant's card payments system.

The restaurant is then told to redirect any card payments to a phone number provided by the fraudster. When the restaurant calls the phone number the fraudster asks to speak to the paying customer and then goes through their security questions.

Once sufficient security details have been obtained from the customer, the fraudster will instruct the restaurant to put the transaction through. The fraudsters then call the customer's bank in an attempt to transfer money to their own account using the security details.

FFA UK works on behalf of the financial services industry to coordinate activity on fraud prevention, and in partnership with the UK Cards Association on industry initiatives to prevent fraud on credit and debit cards.

Katy Worobec, director of FFA UK, said: "It is important that restaurant owners are alert. Fraudsters can sound very professional.

"If you receive any calls from your bank claiming there is a problem with payments, make sure you phone them on an established number to confirm the request is genuine. In addition, always wait five minutes to ensure the line is clear, as fraudsters will sometimes stay on the phone line and pretend to be your bank."

Its intelligence suggests that restaurants in London's West End, as well as Twickenham and Canary Wharf, have been targeted.