The increase in sales is the third consecutive record week with sales for the week to Saturday 19 December at £112m. Online sales are also improving, with a sales increase of 7% on the same period last year.
Due to freezing weather conditions the retailer has seen dramatic increases in sales of outwear, hats, scarves and earmuffs. Gift foods, electronic games and traditional board games sales are also the best on record.
Andrew Murphy, director of operational development for John Lewis, said the new record week "shows how much customers value John Lewis".
He added: "There is a real festive buzz in all our shops as customers are buying last minute presents, with many choosing home technology gifts such as digital cameras and radios. The cold weather also means that sales of fashion, in particular childrenswear, are seeing record-breaking figures."
John Lewis unveiled its Christmas ad activity on 15 November, with the TV ad featuring the Guns & Roses track Sweet Child O' Mine.