New figures from Kantar Worldpanel show that competition among the big supermarket groups here continues to increase.
Supermarket share figures for the 12 weeks to March 1 show that while Tesco remains Ireland's largest supermarket with a 25% market share, that is down from 26.4% the same time last year with sales down 3.6%.
One in every €4 spent on groceries in Ireland is spent in Tesco.
However, the figures show that sales at Dunnes jumped 6.5% in the 12-week period to bring its market share up to 23.4% from 22.3%.
Kantar Worldpanel noted that Dunnes successfully encouraged its customers to buy more and managed to grow the number of trips where €100 or more was spent by an "astonishing" 25%.
SuperValu's 0.4% sales growth put it almost on parity with Tesco and its market share stood at 24.9%.
The supermarket chain has attracted an extra 50,000 customers this year which means that three-quarters of Irish households shopped in SuperValu in the 12 weeks under review, said David Berry, director at Kantar Worldpanel.
Both of the main discounters here continue to perform strongly with both Lidl and Aldi reporting growth of 10.7%. Lidl's market share rose to 7.6% from 7%, while Aldi's increased to 8.1% from 7.5%.