The former cabinet minister, now non-executive director of ad agency Clemmow Hornby Inge, disagrees with last week's proposal from the Institute of Practitioners in Advertising to shake up the traditional format of party political broadcasts.
The proposal followed the Electoral Commission's suggestion last month that
30-second TV ads could invigorate future campaigns. There was a huge drop in turn-out at last year's general election.
"I think we've reached the limit of soundbite politics and to extend that to 30-
second ads on TV would be a mistake," Mandelson told Marketing.
Mandelson, formerly director of communications at the Labour Party, is often regarded as the architect of the political soundbite.
"While advertising will continue to play a major role, I don't think it will be quite the dominating element, or attract quite the spend, of previous elections," he said.
Liberal Democrat director of communications David Walter said: "The danger of abolishing party political broadcasts in favour of 30-second ads is that it places more power in the hands of those parties that can afford slick ad campaigns."
A Tory spokesman said it would look at any proposals that "might re-engage young people in the political process". Labour declined to comment.