Dunnes and Superquinn have both lost more than 3 per cent of their share of the grocery market in the last 12 months, according to figures from Kantar Worldpanel.
Tesco has extended its lead at the top of the survey and had a 27.9 per cent share at the end of last month, up from 27.7 per cent (a 1.3 per cent rise) at the same point last year.
Dunnes saw its share slip from 24.1 per cent to 23.1 per cent (a 3.2 per cent fall) year on year.
Kantar Worldpanel said there were positive signs for Dunnes in the lead up to the busy Christmas trading period, with sales having strengthened since September, when they declined by almost 8 per cent.
Supervalu remains in third place in the survey, with its share decreasing to 19.4 per cent (down 0.2 per cent year on year).
Discount retailer Aldi saw its share of the market increase by 31.5 per cent in the year to the end of November to 6.2 per cent.
Aldi and Lidl, which grew its market share slightly to 6.2 per cent, now both have a larger market share than Superquinn, which saw its market share slip by 3.1 per cent to 5.3 per cent.
Other outlets, which include stores such as Spar, Centra, greengrocers, butchers, Marks and Spencer and cross border retailers, saw their share fall by 5.3 per cent to 11.7 per cent.
Kantar Worldpanel said grocery inflation was at 4.2 per cent at the end of the 12 week period to November 25th, the highest level since a reading of 4.4 per cent in August 2011.
