The post-Christmas period is said to be particularly important for a number of retail sectors, such as fashion
High street shops are hoping for a St Stephen's Day sales boost - with customers looking for a bargain.
However research has suggested online sales could affect in-store trading.
The emergence of the Black Friday phenomenon has already meant a slight drop off in footfall for certain retailers.
Retail Ireland has previously said it expects this to be the best Christmas for retail since 2008, including an annual rise in December sales worth €150 million.
Their Director, Thomas Burke, said Irish retailers are trying to make it 'as convenient as possible' for customers, and that 'click-and-collect' services have seen 'record growth' over the last few months.
Meanwhile Retail Excellence Ireland has reported a strong start to this year's sales.
The group's head of public affairs, Lynn Drumgoole, says "retailers are reporting increased trading levels when compared to last year and average transaction values are up.
"The post-Christmas period from the 26th-31st December is the busiest and most important time for many, and fashion retailers in particular... Footfall will increase further over the weekend and into next as more stores commence their post-Christmas sales" she added.