This is according to Retail Excellence, a representative organisation which supports Irish retailers, who put the blame for the decline down to Brexit, Donald Trump winning the US election and online shopping.
They say the trend is concerning and is placing additional challenges on the sector.
Lynn Drumgoole, Retail Excellence Communications Director said:
“We have also seen a measured increase in Black Friday shopping at discounted prices.
“We have witnessed a significant increase in shopping with .co.uk websites in November due to weakened sterling.
“These reasons, added to a general deterioration in customer sentiment, have resulted in a challenged retail situation so far in December.
“While some sectors will trade slightly up or on par against last year consumer electronics, beauty and pharmacy, telecommunications, ladies wear, footwear and jewellery are all trending downwards.”
At the same time, couriers and logistics companies are reporting a 30% to 80% increase in packages arriving into the country from the UK.
The largest increases in parcel deliveries for Christmas 2016 were recorded in Co Wexford, Tipperary and Laois.
Ms Drumgoole noted that retailers still have very two “very important” Saturdays before Christmas day.
“However at this juncture the situation is concerning,” she added.