Prices over the period rose by an average of 7.8% on average, Kantar said.
As an example, in the four weeks to 4 September, the price of back-to-school essentials (bread, ham, cheese, yoghurt, cereal and milk) rose by 19.5%, making a basket of these products €2 more expensive, Kantar said.
"As food and drink prices continue to climb alongside increasing pressure on other household bills, the impact is unavoidable for many Irish consumers," commented Emer Healy, Kantar senior analyst.
"The average annual grocery bill could go from €6,985 to €7,753 – that’s an additional €768 a year that Irish consumers will have to spend if they do not make any changes to what they currently buy or where they shop."
Grocery price inflation is now at its highest level since Kantar began tracking inflation in May 2008.
Supermarket own-brand lines appear to be benefiting the most from the cost of living crunch, with sales of private-label products rising 5.8% in the period, representing an additional €72 million per year. In addition, value-based private-label ranges saw growth of 21.4%.
Sales Growth At Dunnes Stores
In terms of the best-performing grocers over the 12-week period, market leader Dunnes Stores reported sales growth of 7.2% year-on-year to sit on a value share of 22.3%, boosted by an increase of new shoppers (+4.7%) and shopping trips (+1.7%).
Tesco, with 21.9% share, saw sales growth of 3.9%, while SuperValu, on 21.4% share, saw sales dip 2.2%. Lidl, which holds 13.2% share, grew sales by 3.5% year-on-year, while Aldi, on 12.7% share saw an increase of 1.4%.