Sainsbury’s like-for-like retail sales excluding fuel fell 2.1% in the 12 weeks to June 6 - the sixth consecutive quarterly decline.
Total retail sales excluding fuel were down 0.6% during the first quarter.
It did not provide a breakdown for the performance of clothing brand Tu.
Chief executive Mike Coupe said: “Trading conditions are still being impacted by strong levels of food deflation and a highly competitive pricing backdrop. These pressures, including the effect of our own targeted price investment, have led to a fall in like-for-like sales for the quarter.”
He continued: “Despite the challenging market conditions, we are confident that we are building on strong foundations and making good progress with our strategy.
“We continue to invest in our broad range of products and services and our multiple channels to market. These areas represent strong future growth opportunities and contribute towards our resilience in the current trading environment.”