Anyone who buys three bottles or more will get a quarter off the price of each wine from August 8-12, in shops and online.
The offer covers fortified and sparkling wines but does not include fine and rare wines, en primeur or gifts.
Head of wine Pierpaolo Petrassi MW said: “We’re delighted to offer our shoppers a new format promotion.
“We know our customers love our 25% off six bottles promotion – so for a long weekend we are offering the same level of discount, but off any three bottles of wine or Champagne instead.
“This will appeal to our customers that don’t want to buy in bulk, especially if they are carrying their bags of shopping home – perfect for our convenience shops.”
The offer is not available in Scotland and there are minimum purchase requirements for online shopping.