The Secretary of State for Trade and Industry will announce the intention to change the law to make on-screen shopping easier. Ministers plan to introduce electronic codes which will be as legally binding as a signature on paper.
Instead of quoting a credit card number, people will be able to use their individual electronic signature for transactions - even buying or selling a house - on the web. They will be able to pay for goods at "virtual checkouts" or put money in the bank.
The new codes would ease introduction of smart cards, which are being considered by the Cabinet Office as part of the drive to make government more efficient. These would allow people to use their electronic signature to claim benefits, pay tax or register a birth without leaving home.
The cards could also contain information on an individual's shopping habits, allowing firms to market more effectively.
The change, expected to form part of an electronic commerce Bill in the Queen's Speech, will be announced in Mr Mandelson's address to the Labour conference tomorrow.
He will say Britain must capitalise on the technologies to be competitive in the 21st century and argue that promoting electronic commerce is crucial. "It puts global marketing and sales in the hands of everyone, especially small firms, at minimal cost," he will say. "We need to make sure all our lives and rules are 'e-commerce' friendly ... to provide the best environment worldwide for business to trade electronically." The DTI's Future Unit, a civil service think-tank analysing change in the way business operates, concluded that a "revolution" is underway in the high street. This could mean that by 2000, 95 per cent of a family's purchases could be made from "virtual hypermarkets" on the internet.
The report says "intelligent shopping" will soon be widespread, saving banks, building societies and shops billions, and making life easier for shoppers.
Middle-men - such as estate agents, travel agents or financial advisers - could become obsolete as companies develop direct relationships with their consumers, the report says. They would be replaced with "one-stop shops", offering a range of services and advice.
Plans to introduce individual smart cards, operated through an electronic signature, are expected in a White Paper on Better Government. Ministers want to introduce kiosks, possibly in post offices, where people could pay tax or claim money from the Government with their card.
But the Future Unit acknowledges concerns that electronic signatures could infringe civil liberties and says the Government must introduce strict regulations to ensure data is protected.