J Sainsbury posted solid sales for its fourth quarter and said it expects challenging economic conditions to continue throughout the year.

Britain's third largest grocery store chain said like-for-like sales in the 10 weeks ending on 16 March rose 4.2 percent, with total sales for that period rising 7.1 percent. Striping away petrol sales, the two figures slow to 3.6 percent and 6.3 percent respectively, the company said in a statement published Tuesday on its website. Sainsbury's also said it had increased its overall gross selling space by around 5 percent last year and that it was well positioned to outperform the retail market in 2013.

"We have delivered strong sales in the fourth quarter, increasing market share and outperforming in what remains a tough retail environment," said CEO Justin King in the statement. Over the quarter, we grew customer transactions to 22.9m per week, serving more customers than ever. In the quarter, we added 163,000 square feet of new space, comprising three supermarkets and 19 convenience stores. Over the full year, we have added 14 supermarkets, eight extensions and 87 convenience stores, bringing our total gross new space to just over 1 million square feet, an increase of approximately 5 per cent, in line with our target. We also opened a new depot in Thameside, dedicated solely for our growing convenience business in London and the South East."

The London-based group was able to gain an advantage last month when it was the only major UK food retailer to gain market share amid the horsemeat scandal which hit sales at rival Tesco plc, according to the research group Kantar Worldpanel, but notching a 4.6 percent growth during the 12 weeks ending on 17 February.

Sainsbury's shares rose 2.5 percent in the opening minutes of trading in London to change hands at 374.3 pence each, extending the year-to-date gain to more than 9 percent.