The Advertising Standards Authority (ASA) wants its powers widened to cover misleading adverts on company websites.

The ASA said at the moment, a company can make wild advertising claims on websites and it is powerless to act because it only has powers to regulate paid-for advertising on the internet. This includes viral adverts, pop-ups and banners.

Youtube, which is free to use, and companies' own websites are not classed as paid-for advertising space.

Matt Wilson, a representative for the ASA, said: "Tesco could say something on their website that breaches the advertising code and we can't do anything about that, but the same statement on a billboard is within our remit."

Wilson said the position only changes if a company 'pushes' the video, such as by email, or encourages users to 'pull' the video from their own website, for example by making it easy for users to download the clip and circulate it among friends.

The Advertising Association set up an industry policy group a year ago. The Digital Media Group comprising representatives of a variety of industry bodies, has been looking at the issue of industry self regulation for advertising on digital media. A report into this is expected in 2009.

Companies making misleading claims should also be aware that these statements could fall foul of the new Consumer Protection Rules. Under the Consumer Protection from Unfair Trading Regulations 2008 it is an offence for traders to mislead consumers.