Buscombe joined forces with Lord (Chris) Smith, the chairman of the Advertising Standards Authority, to seek clarification of regulations implementing European Union directives on unfair commercial practices and misleading and comparative advertising.
Industry bodies had previously warned that the regulations would lead to a ban on "buy one, get one free" offers.
Buscombe told a House of Lords debate that "buy one, get one free" offers were extremely popular with consumers. "In my view, it would be a great pity for both marketers and consumers if any interpretation could be placed on the Consumer Protection from Unfair Trading Regulations whereby such offers and similar marketing practices could be considered in breach of them," she said.
Lord Tunnicliffe, a Government spokesman, replied: "In the matter of ‘buy one, get one free' offers and free gifts with purchases, I agree these are well-established marketing practices in the UK and not in themselves misleading.
"We do not believe that the specific prohibited practice relating to the use of the description ‘free' will prevent the use of the word ‘free' in these cases."
He told Lord Smith that the new rules would be enforced proportionately. "We strongly believe that where good practice has been established, particularly by the Advertising Standards Authority, these regulations should use and build on that good practice," he said.