Troubled value retailer Instore has blamed the collapse of Woolworths for a 1.92% fall in like-for-like sales for the five weeks to 3 January.
The retailer, which operates the Instore and Poundstretcher fascia, said the value sector had been "significantly affected" by the heavy discounting at Woolworths throughout the run up to Christmas.
Total sales for the 18 weeks to 3 January rose just 0.52%, but fell 0.7% on a like-for-like basis.
The group warned it expected to report a full-year loss of between £4.5m and £5.0m, but said its banking partners remained supportive of its plans to bring the company back to profit.
Instore's figures go against the fortunes of rival Poundland, which this week said like-for-like sales had increased by 3.9% in the five weeks to 4 January, with overall sales up 24%.