The ASA assessed more than 1,500 posters - 80 per cent of the total - during a six-month period in Greater London. It followed the publication of research showing that nine out of ten consumers want advertisers to be more cautious when using outdoor.
The majority of the breaches were in the food-and-drink sector, with the poster campaign for Shark soft drinks accounting for the majority of the complaints.
The computer and telecoms sector was the second most problematic market - Telewest's "Stay on the bloody phone" campaign prompted 261 complaints.
The holiday sector accounted for 14 per cent of the breaches.
However, the ASA noted that although the 1 per cent found in breach of the codes had been identified and had had complaints about them upheld, there was still a number giving cause for concern.
Alan James, the chief executive of the Outdoor Advertising Association, said: "This very useful survey shows the extremely high compliance rate in the poster industry."