For the 12 weeks ending August 16, Dunnes Stores posted the strongest sales growth with 8% and was closely followed by Lidl with a 7.7% increase, according to Kantar Worldpanel.

Overall, sales have grown 1.4% year-on-year across the Irish grocery market, the best performance since March 2015, it said.

David Berry, director at Kantar Worldpanel, said that Dunnes’ success is in large part thanks to the continuation of its ‘Shop and Save’ campaign.

“Although fewer people have shopped with the retailer this period, these customers have been encouraged to spend more, with the average shop now costing €34.50 – an increase of more than €5,” he said.

Kantar said that Lidl has maintained its strong performance, boosting its share of the market by more than half a percentage point to 9.1%.

Sales growth of 7.7% has been driven by an increased number of shoppers returning to the store more frequently and spending larger amounts on each occasion, it said.

Lidl is the only retailer to drive improvement in all three of these areas in the past quarter, Kantar said.

“We’ve seen Tesco’s performance improve in recent months, and the past 12 weeks are no exception – sales decline now stands at just -1.0%.

“As its performance continues to improve, Tesco retains the number one position in the market with 24.8% share, despite an ongoing tussle with Supervalu for the top spot.

“An increase in customer numbers, with more than 20,000 new shoppers recruited this year, has played a vital part in the supermarket’s recovery,” he said.

Supervalu has retained second place, Kantar said though close competition continues as the second largest retailer remains just 0.3 percentage points behind Tesco, with 24.5% of the market.

Aldi has seen sales grow by 3.8%, lifting its share of the market to 8.7%, it said.