The Office of Fair Trading (OFT) has warned retailers about tricking customers with misleading price offers.
In a report issued on Thursday, the OFT vowed to take action against High Street and online firms which break the law by not making price offers clear.
One practice the OFT is worried about is “drip” pricing, where compulsory costs, such as delivery charges, are added during the buying process.
But the British Retail Consortium said any new legislation would be pointless.
Other practices the OFT said it was concerned about were time-limited offers such as “offer ends today”, and the advertising of “sale” products with only very limited stock in order lure customers through the door.
The OFT said such promotions were no unlawful, but could be against customers’ interests.
The regulator said it obtained its information from consumer surveys, focus groups, psychology literature and “groundbreaking behavioural economics research”.
There was plenty of evidence that certain pricing techniques can lead consumers into buying decisions they would not have made were prices more clearly advertised, the regulator said.
John Fingleton, OFT chief executive, said: “It’s an important issue because it affects all of us as consumers, but it’s also important because it affects how markets work across the British economy.
“Today we are urging businesses to review their pricing practices in the light of our report and we will, where necessary, take enforcement action against firms that don’t have their house in order.”
However, retailers said customers were a savvy bunch who knew when they were being mislead.
Tom Ironside, BRC Director of Business and Regulation, said: “Customers aren’t stupid. They make sophisticated judgements about prices and value within stores, between stores and over time and have all the information they need to do that.
“Discounts and promotions are part of our highly competitive retail market and customers benefit from them,” he said.
The BRC said that there are currently a record number of promotional deals on offer, at a time when household budgets are feeling the squeeze.
Latest figures show 37% of fast-moving consumer goods are on some sort of promotion or discount at the moment, which the BRC said is an all-time high.
Mr Ironside said: “BRC members abide by the rules and regulations governing price advertising. They want satisfied customers who come back again and again.
“They would have nothing to gain from attempts to mislead and any extra legislation or over enforcement on this issue would therefore be pointless.”
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