NSW has banned service stations from misleading drivers by giving priority to displays of shopper docket discount prices.
As of September 1, petrol stations must display the full cost of petrol on their price boards, and not the price after discounts from shopper dockets and other deals.
Any discounts must be displayed separately.
"Motorists wanted truth in fuel pricing," the minister for fair trading, Anthony Roberts, said on Sunday.
"The days of service stations enticing customers by advertising the discounted price for regular unleaded petrol that only holders of shopper docket vouchers were entitled to are over."
Petrol retailers are also required to display the prices per litre of their top two selling fuels by volume, as well as diesel and LPG.
Previously, only regular unleaded prices had to be displayed.
"Motorists will no longer be confused about the real cost of fuel as they approach a service station," Mr Roberts said.
NRMA president Wendy Machin said the changes were a win for motorists.
"Too many motorists were caught out by price boards that didn't display prices for popular fuels or included discounts from shopper dockets," she said.
The ban on misleading roadside price promotions follows a review by Fair Trading, which found petrol retailers were confusing customers by advertising special offers.