A walk down Pitt Street Mall on Saturday showed large discounts of up to 70 per cent in major retailers including Myer, Top Shop, Country Road and Portmans.

Only a few years ago, Christmas sales were unusual in the weeks before Christmas, with Boxing Day sales marking the start of end-of-year discounting.

"It's fair to say retailers have seen [Christmas] sales a bit lighter this year, compared to last," Australian Retailers Association executive director, Russell Zimmerman said.

But Mr Zimmerman said there should be a turn-around in sales in the next week, with forecasts expecting a record $14.1 billion across NSW for the year, up 6 per cent on the previous year.

The pattern of pre-Christmas sales has emerged against a range of factors, as retailers introduce discounts as a strategy to boost their sales.

Personal finance commentator from credit comparison website, Finder.com, Michelle Hutchison said the early discount period indicated the power of online sales.

"Traditional retailers are having to go to any length to encourage people to come in store," she said, offering some more good news to consumers.

"If stores are dropping their prices this much now to keep up with online, they will cut prices even further in the Boxing Day sales."

The general manager of Myer's NSW stores, Louise Pearson, said the chain is offering discounts between 15 and 40 per cent off on fragrances, toys and food, in order to keep up with other other retailers.

"There's no doubt retailers are on sale and it's a really competitive marketplace," she said. "Every year shoppers can come in and expect good discounts on gift items before Christmas."

Claire Barker from Point Piper said she left her Christmas shopping until the last minute this year, and was surprised at the increase in discounting.

"Most of the places we would normally buy from are, as of this week, offering up to 70 per cent off," Ms Barker said. "For example, one present [a leather handbag] was reduced from $1690 to $1183. We couldn't believe it."

Mr Zimmerman expects the record low interest rates and an extra day of trading before Christmas Day on Thursday will see retail trading remain buoyant this week.

"We know people leave their Christmas shopping until the last minute and there are still a lot of presents to be bought," he said.

with Angharad Owens-Strauss