The NCA, a statutory body, found that more than a quarter of those surveyed were now spreading their weekly shopping spend over different supermarkets, and that more than a third were opting for own-brand products over big brands because they were seen to offer better value.
The main beneficiaries of the changing trend have been the discount chains, with 61% of consumers now doing some of their shopping at Lidl and 54% at Aldi.
NCA chief executive Ann Fitzgerald, who has been openly critical of the lack of price competition between the market's two biggest players, Tesco and Dunnes, welcomed the more discerning approach by consumers. A series of surveys by the agency, including one showing that a basket of branded goods cost 30% more in the Republic than in Northern Ireland, had made shoppers more aware of "the substantial price differentials" between discounters and the established supermarket chains, she claimed.
"An informed consumer is an empowered consumer, and using the information from grocery price surveys, shoppers can drive competition in the sector by spreading their spend," she added.
The survey findings were welcomed by Paul Foley, Aldi managing director for Britain and Ireland. The credit crunch offered an opportunity for the chain, he said, "because more people will think about shopping with us".
However, Tesco and Dunnes, who together have over 50% of the market, have been hitting back with high-profile price promotion campaigns. In full-page ads in the Irish national papers this week, Tesco promised "every week we'll cut prices", while a similar Dunnes' promotion pledged "many more special offers every week".