Motorists are now able to access real-time fuel price data through apps to assess what the nearest and best petrol price is.
All petrol retailers must now submit their prices to an aggregator, with the data then available for app developers to use.
Any change in price must be updated within half an hour, or the retailer risks facing a hefty fine.
When announcing the launch of the scheme Attorney-General Vickie Chapman said the scheme ensures motorists are better informed, helping to deliver cost of living relief to households across SA.
The Productivity Commission estimates that access to real-time fuel pricing information will save motorists more than $3 million a year.
Consumer and Business Services Commissioner Dini Soulio says his team will be closely monitoring retailers to ensure they are complying with the new laws.
"In the lead-up to the launch of this scheme, my staff worked closely with retailers to ensure they understand their responsibility," Commissioner Soulio said.
"We have also commenced a tender process for a data validation service, to ensure accuracy and validity of fuel prices," he said.
The RAA's motoring expert, Mark Borlace, says this scheme will be particularly beneficial to motorists near the end of a petrol price cycle.
"Prices tend to jump around and differ greatly at the end of a cycle, so this scheme will help motorists find the cheapest price.
"The RAA is using this aggregated data to inform its app, which is free for all South Australians. It will allow motorists to search for the best price, and map their route to get the best deal, every day", Mr Borlace said.
The Marshall Liberal Government's real-time fuel price scheme will run as a trial for two years.
More information -- including apps that are now available and sourcing real-time data from South Australia, as well as details on how to report service stations that have not updated their information -- can be found at www.sa.gov.au/fuelprices