Debenhams triggered the battle after it started a 25% off 'New Season's Spectacular' sale on a range of new stock on Tuesday.
House of Fraser will also be running 25% off promotions instore and online across both womenswear and childrenswear. The move follows a buy one get one free promotion on all menswear last week.
John Lewis is responding in kind with its 'Never knowingly undersold' policy which means that it is obliged to monitor and immediately price match its competitors.
Nat Wakely, director of selling operations, said: "John Lewis customers know that through our pricing policy we proactively seek out the lowest price for any product and match it immediately. We even match sale prices."
The three retailers are going head to head until Sunday in an attempt to lure reluctant shoppers to part with their cash.
Michael Sharp, Debenhams deputy chief executive, said: "When times are hard we have a duty to give customers better value than ever.
"All this activity is planned and there is no other retailer better placed to deliver it."
The battle is reminiscent of the pre-Christmas period, when a range of retailers on the struggling high street engaged in a similar promotional battle.