Tesco has maintained the slimmest of leads in the battle to be Ireland's biggest supermarket chain. 25 percent of Irish shoppers favour Tesco - while SuperValu's share has grown to 24.9 percent.

Musgrave's SuperValu has been closing the gap on Tesco since it merged with SuperQuinn, taking over 24 of its stores.

SuperValu now serves 2.6m customers every week - and it plans to invest €18m in opening four new stores in 2015.

Dunnes Stores' performance has also improved, it is the third biggest chain and catching up with the two dominant players. In the 12 weeks to the end of February its sales increased by 6.5 percent, taking its share of the market from 22.3 to 23.4 percent.

Discount German retailers Aldi and Lidl are still the fastest growing supermarket brands in the country - they now account for a combined 16.7 percent of the market.