A basket of 28 own-label items in the Irish Republic is more than 50% cheaper in Lidl than in Tesco or Dunnes, according to a pricing survey by the National Consumer Agency.

The statutory body's findings have sparked a war of words, with Tesco taking full-page advertisements in Irish national newspapers to dispute it, and offering its own price list of 14 items on which it claimed to be cheaper. Lidl responded by claiming it was officially "the cheapest retailer in Ireland".

The survey found that Lidl's own-label yoghurt, for instance, cost 47 cents (about 35p), but Tesco's was €1.99. Lidl ice cream was 64 cents, compared with €2.32 for Tesco's.

An own-label pizza sold at €1.16 in Lidl was compared with a pizza that cost €2.94 in Dunnes.

"Just because they're called discounters doesn't mean their goods are of low value," said NCA chief executive Ann Fitzgerald. "It's up to customers to make up their own minds about quality, price and value."

She added that the price war that was widely expected following abolition of the Groceries Order in 2006 had never materialised and claimed there was "virtually no price difference" between Tesco and Dunnes.

Fitzgerald also welcomed the emergence of SuperValu, the Musgrave-owned franchise chain, as "a real competitor" to the multiples. And she encouraged consumers to split their weekly shopping between different stores to ensure best value.