Both Australian retailers and shoppers alike are gearing up for a busy and frenzy Boxing Day post-Christmas sales middle of this week.

The post-Christmas sales period, according to the Australian Retailers Association, expects to take in $14.8 billion this year. The association expects $7 billion will most likely be spent on non-food and other discretionary items.

To cash in on this huge amount, retailers like Myers and David Jones have announced starting their annual stocktake sale earlier than the expected Boxing Day D-Day event through their respective virtual online stores.

"It's . . . at a time when all the bricks-and-mortar stores were closed," Steve Carey, Myer spokesman, was quoted by The Australian. "It's also giving customers more time to shop online at a convenient time."

The Australian Retailers Association said around 120,000 shoppers are expected to advantage of the post-Christmas Boxing Day sales event.

"It's a genuine sale and customers recognise that," Paul Zahra, David Jones boss, said.

"We expect it to be the best clearance ever," he said. "It's an important time and we expect it to be big.

"We've seen year-on-year increases for clearance and when you add other channels, people have even more options to buy."

Russell Zimmerman, Australian Retail Association executive director, believes the early kickstart of the post-Christmas Boxing Day sales period signifies the start of things for Australian retailers and the way the nation's shoppers do their thing.

"I think that just proves how important the online area is, how it's growing and how Myer and other retailers will see that moving forward," he said.