Companies must not be allowed to pay to have their products featured in British TV shows, a consumer body has argued.
Product placement is rife on US shows such as American Idol
The National Consumer Council (NCC) has said product placement, which is common in the US but banned in the UK, would undermine trust in broadcasters.
Media regulator Ofcom is looking into whether the rules should be relaxed.
Commercial broadcasters want new ways to raise money as audiences fragment and it becomes easier to skip adverts. The BBC would not be affected.
In the US, American Idol judges drink from prominent glasses of Coca Cola, Desperate Housewives has promoted Buick cars and characters in 24 extol the virtues of Cisco computer security.
Proposed changes to European Union law could make such in-show advertising legal in Europe.
The NCC's Sue Dibb said: "UK broadcasting is some of the best in the world. We love the standard of our programmes here.
"Product placement would seriously undermine that. For broadcasters, the editorial integrity of programmes and the trust that we then as viewers have in British broadcasting would be fundamentally undermined.
"That's why we're saying to Ofcom, 'Don't go down this route'."
The rise of digital TV has made the competition for viewers and advertising revenues more fierce than ever.
And hi-tech developments such as TV on demand and personal video recorders make it simpler to bypass traditional ad breaks.
A spokesman for the regulator said: "Ofcom welcomes the NCC's response to the consultation and recognises there are strong feelings for and against the introduction of product placement.
"This, along with other responses, will be offered to the government to help inform it during its participation in the debate."
In November, unions representing US writers and actors called for a code of conduct to govern product placement so viewers would be told if they were "subject to hidden or stealth advertising".