Petrol companies in New South Wales could face fines of up to $110,000 for failing to display the full price of fuel.

The NSW Government has banned petrol stations from only displaying discounted fuel prices available to drivers using grocery shopper dockets.

Mr Roberts says Woolworths and Coles will still be able to advertise the discounts, but the price on the board must be the real price.

"Service stations in New South Wales will now be required to display the real price of fuel without any discount offer," Fair Trading Minister Anthony Roberts said.

"Fuel stations that aren't compliant will face fines of up to $110,000 for a corporation and $22,000 for an individual."

He says inspectors from the Fair Trading Department will be out in force to make sure motorists are getting a fair deal.

"For far too long there's been a lack of openness and transparency within the market place," he said.

"What we've found is that major companies have been using shopper dockets and various other discounts to lure motorists in."

Petrol stations will also be required to display the price of the two top selling fuels for the past six months, as well as LPG and diesel if they are sold.

"What we found is that there was a huge discrepancy between the price of the usually signed E10 and the very rarely signed premium fuel," Mr Roberts said.

"So if you were a premium fuel car driver, you quite often didn't know the price of your fuel until you actually pulled up to the pump.

"What that meant is that companies were making sure premium fuel customers were paying 10, 11, 12 cents more per litre, than E10."

Regulations to create 'level playing field'

National Roads and Motorists' Association (NRMA) research shows 95 per cent of motorists think the advertising is misleading, while half ended up paying more for petrol they thought was cheaper.

NRMA president Wendy Machin says the new regulations will create a level playing field for retailers without discounts or special offers.

"There's an inquiry going into shopper dockets. It will be interesting to see what that says," she said.

"We do not believe the supermarkets are giving us anything for free, so if we're getting anything from 8 to 45 cents a litre discount at the pump I'm pretty sure we're paying for that at the checkout in the supermarket."

The Service Station Association says regulations banning the inclusion of shopper docket discounts in petrol prices in NSW is a good move for smaller fuel operators.

Association spokesman Colin Long says there is still not 100 per cent compliance with the new regulations despite having 12 months to work towards it.

"Some of the major companies are dragging their feet. They're probably just seeing how the land lies," he said.

"They're also probably waiting for the national agreement which didn't come, but to New South Wales' credit it's preceding and it's been very clear about it for 12 months notice.

"There's been adequate notice there, so in terms of the bigger oil companies they really need to pull their socks up."