John Lewis , Britain's biggest department store chain, posted a 9.3 percent year-on-year rise in sales over the Christmas trading period, gaining market share and placing it firmly in the festive winners' camp.

The employee-owned retailer said on Wednesday its sales were 596 million pounds in the five weeks to December 31.

It said sales at stores open over a year were up 6.2 percent, while online sales soared 27.9 percent.

John Lewis said sales in the electricals and home technology category were up 4.0 percent, with fashion and beauty up 10.3 percent and homewares increasing 13.6 percent.

The firm said in the week to December 24 sales jumped 32.7 percent. They fell 4.8 percent in the following week as the comparative week last year was the week before the VAT sales tax increase on January 1 2011.

Trade in 2012 will undoubtedly be challenging and economic conditions volatile, said Managing Director Andy Street.

Earlier on Wednesday Next , Britain's No. 2 clothing retailer, posted a 3.1 percent rise in sales for the August 1 to December 24 period but took a cautious view on the outlook for 2012.

(Reporting by James Davey; editing by Sarah Young)