The latest supermarket share data from Kantar Worldpanel in Ireland shows that the grocery market has fallen by 0.9% compared with the same period last year.
Kantar Worldpanel Ireland monitors the household grocery purchasing habits of 3,000 households in Ireland.
Discount retailers and own brands are capturing more market share with Aldi and Lidl now accounting for 12.4% of the total market. This is for the 12 weeks to 5 August, 2012.
Aldi showed the strongest growth with a 25.2% increase when compared to the same time period last year.
Tesco still leads the way with a 28.8% market share, an increase of 3% from the previous 12-week period.
Supervalu, Aldi and Lidl all saw growth. However, Dunnes Stores and Superquinn saw a decline.
Value for money is driving growth of own brand groceries.
Commercial director at Kantar Worldpanel David Berry said: "Value for money remains at the top of the agenda for shoppers who are becoming more selective about which products they buy and where they buy them.
"This has meant we have seen a surge in sales of retailer own brand goods across most categories, with everyday staples, such as bread, breakfast cereals, biscuits and soft drinks, doing well in particular.
"In fact, over the past two years ambient own label ranges like these have gained an additional four share points within the total market."
Grocery inflation stands at 2.1% for the 12-week period ending 5 August 2012, down from 2.7% in the previous period, but significantly below the 4.4% seen in August 2011.