Sainsbury's sales are picking up

The firm said like-for-like sales - which ignore the effect of new store openings - were up 1.3%, excluding petrol, in the 12 weeks to 18 June.

Sainsbury's chief executive Justin King said the sales figures represented "continued progress".

The supermarket chain is in the midst of a three-year recovery plan aimed at regaining ground on its rivals.

Total sales for the quarter were up 5.7%, or 5.3% excluding petrol sales, Sainsbury's said. Like-for-like sales including petrol were 1.9% higher.

Customers are increasingly seeing the benefit of our better availability Justin King, Sainsbury's chief executive See Sainsbury's share price

"We are encouraged by our trading performance in the first quarter of this financial year which shows sustained underlying sales growth," said Mr King.

"Given the more difficult and competitive grocery retail market over the past three months, like-for-like sales growth of 1.3% represents continued progress."

Fuller shelves

The cost of Sainsbury's turnaround plan was the main cause of the slump in annual profits - down to �15m from �610m the previous year - reported last month.

The supermarket is seeking to improve product availability by sorting out IT and delivery problems which had hit its supply chain.

Mr King said there were signs this was now being rectified with customers "increasingly seeing the benefit of our better availability".

He also said he was "pleased" at news that Sainsbury's market share is growing again.

Recent figures from market research firm TNS showed Sainsbury's closing in on the UK's second-largest supermarket chain, Asda.