Australian shoppers are splashing big cash in the post-Christmas sales, but some small businesses say they are not feeling the love.

The week between Christmas and New Year is expected to generate $3.83 billion in spending nationally, up 4.4 per cent on last year, according to forecasts by the National Retailers Association.

Demand is being driven by Boxing Day discounts and the redemption of Christmas gift cards.

Diana Derek's Canberra homewares store has been running at a loss since Christmas and she's worried consumers have overlooked small businesses. (ABC News: Lily Nothling)

But at Diana Derek's Canberra homewares store and boutique Hive, sales have plummeted, and she has been running at a loss since Christmas.

"There's been a massive drop off … we didn't plan for that," Ms Derek said.

"I assumed that it was just because everyone goes to the coast [after Christmas], but I went into the Canberra Centre and did see a lot of Canberrans shopping.

"Unfortunately, it does look like they've chosen the malls over the little businesses."

Canberra Outlet Centre was packed with shoppers searching for a bargain on Boxing Day.  (ABC News: Callum Flinn)

Her small store is unable to compete with the sweeping discounts offered by large retailers.

"People just get so overwhelmed with the word sale, [but] it doesn't mean it's quality — mainly what we see is quantity," Ms Derek said.

The Canberran took over the shop six months ago with the hope of keeping the almost 30-year-old independent business running.

"You start wondering if you've done the right thing," she said.

"It would be great if people kept supporting it because we won't survive and we will get pushed out by the big guys."

Ms Derek says if shoppers always overlook small businesses, they will soon disappear. (ABC News: Lily Nothling)

Sales a double-edged sword

Canberra Business Chamber chief executive Greg Harford said big sales periods like Black Friday and Boxing Day could be a double-edged sword.