"For the week before Christmas, we have a 50pc-off gift event which is about giving our customers real value for money at a time when they need it the most," Karen Nason, spokesperson for Debenhams, told the Herald.
Selected items have been reduced with some Jasper Conran dresses reduced by 70pc and John Rocha bags down by 30pc.
The store rates luxury shoe designer Jimmy Choo and global perfume brand Chanel No 5 as their best sellers this Christmas.
"We are expecting to sell over 100,000 bottles of perfume and beauty gift sets this week -- with Jimmy Choo and Chanel No 5 having been our top performers so far."
Dublin's oldest department store, Arnotts, has experienced a surge in sales and is expecting increased footfall in the coming days.
"Customers are starting to shop from as early as 8am and are availing of the extended opening hours, until 10pm and business is growing on last year," said Leesa Kavanagh, retail director at Arnotts.
The store also has reductions and the Herald found a pink multi-colour tabby dress that had been reduced by two thirds from €155 to €54.50.
Ms Kavanagh said that some brands were reduced early in order to avoid the sales rush in January and to give customers early option on certain items.
"Our winter sale is starting at 9am on December 26, however, some brands go into sale early so there are some very early seasonal discounts to be availed of."
Among the store's best-selling items are beauty gift sets which are boosting their online sales and iPad Minis, which are selling out.
"Ciate caviar manicure sets are proving very popular and mini iPads are now like gold dust with deliveries selling out on the same day that they arrive," added Ms Kavanagh.
While each Christmas is usually associated with the latest gadget when it comes to toys, the old favourite, Lego is making a big comeback.
"Lego Mine for boys and Lego Friends for girls are among our best sellers," said Donna Simpson, manager in Smyths Toy Store.
"The Furby would also be among our best-sellers and Leap Pads have sold really well as well and Jake's Musical Pirate Ship is also flying out."
Clerys Department Store, which is now under new ownership, have also announced their Christmas sale will start tomorrow with reductions of up to 50pc.