Yesterday’s Boxing Day sales are being hailed as a bumper period for retailers, with more than $2 billion going through the tills.

Australian Retailers Association’s Russell Zimmerman said crowds were so big on Thursday that many stores were forced to restrict entrance to stores.

He said he expected that more than $2 billion was spent on the big festive sales’ day.

“If sales continue like those we saw yesterday throughout the post-Christmas period, the $15.1 billion predicted in sales will be exceeded,” he added in a statement.

The ARA is forecasting $15.1 billion to be spent during post-Christmas sales from Boxing Day through to mid-January.

If achieved, that would be an almost four per cent rise on last year’s $14.5 billion worth of sales turnover.

The National Australia Bank said transactions through its system were up 25 per cent on Boxing Day to 4.78 million.

At the peak, NAB said it was processing more than 127 transactions a second.