Retailers predict stores around the country will take in more than $15 billion over the next three weeks, with the bulk of that likely to be spent on Boxing Day.

“It’s been a reasonably good Christmas,” Australian Retailers Association executive director Russell Zimmerman told AAP from Sydney’s Pitt Street Mall on Tuesday.

“As I look around there’s a fair few bags in people’s hands so that’s a good sign.”

He expects “a huge number of people” to head for the Sydney CBD shops and other malls around the country for the Boxing Day sales starting on Thursday.

NSW Fair Trading Minister, Stuart Ayres, said people should ensure they were familiar with store return policies.

“Sales can be exciting and tempting but please don’t get caught out with a lasting hangover,” he said.

NSW Fair Trading fielded almost 14 per cent more complaints involving refunds over the last Christmas period than the 2011 holiday season.

Ayres said it also paid to do homework when shopping online.

His tips are to make sure you know who you are dealing with, be wary of offers that appear too good to be true and shop around for comparisons.

Some stores were starting online “Boxing Day” sales as early as Christmas Eve.

But Zimmerman didn’t think the lure of early sales online would take away from the familiar frenzy seen in department stores on the day.

“There’s a real atmosphere around Boxing Day sales, it’s full of people, it’s full of excitement and noise and generally speaking there’s entertainment around,” he said.

“You may well find that people will be encouraged to come out, they’ll think it might not be quite so busy as it’s been in the past because of the online sales, but I suspect it will be just as busy.”

AAP