Tesco is already pushing hard on price with its Big Price drop strategy, which has dropped the price of 3,000 products as part of a £500m commitment.
Asda already pledges to give customers the difference if it is not 10% cheaper on customer's comparable grocery shopping, while Waitrose is drawing attention to its Tesco Price Match promise in its marketing campaign.
The 'Sainsbury's Brand Match' scheme will give customers a voucher when they check-out, which will refund the price difference if the branded goods cost less at Asda or Tesco.
Price data supplied by market data firm Brand View instantly checks whether the prices at Tesco and Asda are cheaper and includes up-to-date promotions in rival supermarkets.
Other supermarkets do not provide the relevant data and so are not included in the scheme.
The initiative coincides with Sainsbury's new marketing strategy, which is based around its "live well for less" slogan.
Sainsbury's has already trialled the Brand Match technology in its 12 stores in Northern Ireland and claims the initiative has been well received by customers.
Sainsbury's group commercial director Mike Coupe said: "Unlike some of our competitors we aren't asking customers to do the hard work to check on our prices.
"We know shoppers don't want the hassle of having to enter different pieces of information on their computer at home before having to then print out a coupon just to check they are getting the best deal."
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