Instead, a Tory government would seek "responsibility deals" with the alcohol and food industries, under which advertising would be based on the existing codes of practice.
The decision puts the Tories at odds with Labour, whose ministers are threatening statutory controls if drinks and junk food firms do not tighten their codes.
The voluntary agreements backed by the Tories would go much wider than advertising. A Tory policy document said: "A responsibility deal on obesity might see companies changing the ingredients of the goods they sell and amending their advertising practices, and schools providing better education on healthy eating."
David Cameron, the Tory leader, said: "Often, responsibility deals get a faster and better result than going down the regulatory or legislative line. Passing a law or regulation can often have an unintended consequence."
He cited calls for a blanket ban on ads during children's TV programmes. "The result would be a wipe out of well-made, originally produced programmes on ITV, Channel Four and other commercial channels."