Adelaide suburban stores have opened for the first time on Boxing Day, with Premier Steven Marshall declaring his government's deregulated shopping hours a "huge success".
The new Liberal government promised to lift all restrictions on trading across SA as an election promise ahead of the March poll.
But efforts to get legislation through parliament failed when the measures were blocked by the Labor opposition and crossbench MPs.
Instead, Treasurer Rob Lucas has used the government's regulatory powers to allow all shops to open on Boxing Day this year.
Mr Marshall said crowds of shoppers had flocked the Boxing Day sales.
"Today's massive turnout is a ringing endorsement of the need for shop trading hours reform," he said in a statement.
"We've said all along, if consumers want to shop, traders want to open and employees are willing and able to work, why should the law stop them?
"My government's view is why shouldn't families in Elizabeth, Noarlunga, Port Adelaide, Tea Tree Gully and Marion have the same opportunity and freedom to shop as families near the CBD?"
The Australian Retailers Association says reform of Boxing Day shopping hours will result in an "exponential" growth in sales for local stores.
"As a result of the newly-deregulated trading hours in SA, we predict South Australians to spend roughly $133 million," ARA executive director Russell Zimmerman said.
But SA's independent retails says the changes will benefit the large multi-nationals to the detriment of small traders.
"Treasurer Rob Lucas is playing politics at the expense of South Australia's largest employer, small business, by extending trading to the large retail chains for the first time," SA Independent Retailers spokesman Colin Shearing said.
"The stop deregulation campaign is calling on the state Liberal government to stop the relentless attack on small family businesses, suppliers and farmers."
Before this year only stores in Adelaide CBD were allowed to trade on Boxing Day.
However, some shops in the suburbs could open, depending on their size and the products they sold.
It's those stores that are expected to lose out with the regulatory changes.
The government has maintained its proposed deregulation of all trading hours will boost jobs, and says no stores will be forced to open.
The legislation also proposed to allow staff the choice of working on Boxing Day and other public holidays or not.
