A new food price survey has found retailer Aldi is up to 47% cheaper than other supermarkets.
The survey, conducted by Grant Thornton, says Aldi has reduced the price of over one-third of its product range in past 12 months.
It examined the prices of groceries at Aldi, Lidl, Tesco, SuperValu and Dunnes Stores.
A basket of 62 own-brand products is more than 17% cheaper in Aldi than Tesco, over 24% cheaper in Aldi than Dunnes Stores (after taking into account their €10 off €50 voucher offer) and up to 47% cheaper in Aldi than SuperValu.
Grant Thornton says individual items are often several times more expensive than Aldi products: e.g. SuperValu in Galway sold Cherry Vine Tomatoes for €4.98 versus €1.69 in Aldi, Dunnes Stores in Cork sold Vintage White Cheddar for €4.99 versus €1.59 in Aldi and Tesco in Dublin sold Orange/Apple Juice packs for €3.38 versus €1.25 in Aldi.
A series of price comparison shops were carried out on consecutive days in Dublin, Cork, Limerick and Galway across the most common grocery items bought by Irish households.
The sample grocery basket - randomly selected by Grant Thornton - was found to cost on average €65.04 in Aldi, €65.53 in Lidl, €76.54 in Tesco, €80.74 in Dunnes Stores and €95.50 in SuperValu.
The comparison of grocery prices | Source: Grant Thornton
The random sample included strawberry jam, fresh cream, honey, ice-cream, rice, orange juice, cheese, yogurt, soda bread and a wide range of fruit and vegetables including cucumbers, mushrooms, apples and broccoli.
Grant Thornton says the survey is "the first comprehensive independent audit of prices at the major supermarkets since the National Consumer Agency’s July 2009 grocery market survey."
It says to ensure the comparison of like for like products, it focused where possible on mid-range own-brand products.
Damian Gleeson, head of retail at Grant Thornton, says: "Our research focused on the five major supermarkets that account for nearly 90% of Irish grocery spend.
"We made a random selection of a basket of 62 items from the most popular purchased lines.
"We found that there are huge differences in pricing of similar comparable products across the board, with significant savings to be made by consumers by shopping at Aldi in particular.
"Aldi offered the lowest prices on general everyday groceries and was up to 47% cheaper than SuperValu, which is the most expensive supermarket surveyed."
In a statement, SuperValu says it has "some fundamental questions" with regard to the price comparison survey.
It says: "Despite requesting the data that the survey is based on and the dates that the research took place on from Grant Thornton this morning, we have not received a response as yet.
"It is unclear which products were used in comparisons and whether those comparisons were valid.
"For instance the press release mentions a price of Cherry Tomatoes 500g that were sold in SuperValu for €4.98. In fact we have a 500g Cherry Tomato comparison product at €1.58. For this reason we would question the validity of the comparisons used.
"Similarly, the report makes reference to money off vouchers from another grocery retailer, but does not reference our voucher offer that is currently live where shoppers can avail of up to €16 off a grocery basket of €80 dependent on the level of vouchers they have redeemed through our Real Rewards loyalty programme.
"As a result some of the media reports being discussed this morning are misleading as they do not give an accurate comparison of prices.
"Any grocery retailer can select a basket of goods from their store shelves, which shows that they provide better value than their competitors.
"A basket of 62 products is not representative of the value on offer in store at SuperValu".