The call follows a BBC Panorama investigation, which found that online ads were being placed on unmonitored, hateful and offensive websites.
The Internet Advertising Bureau has attempted to restore confidence in the industry through an audit of the 13 networks that have signed up to the Internet Advertising Sales House (IASH), but media agencies say its actions do not go far enough.
One digital media director said the real question was which sales houses have not signed up to IASH. 'Google has an extensive ad-targeting network, but has not applied to IASH,' he said. Google did not return calls for comment.
Separately, the IPA is exploring additional protective measures for advertisers.
- What you don't know can hurt you, page 15.