There's no guarantee the Government's latest petrol policy will make any difference to consumers, says the Automobile Association (AA).
The Fuel Market Bill aims to introduce more competition into the industry, and the Government says motorists could be saving up to 30 cents per litre at the fuel pump within one year.
But Automobile Association (AA) principal advisor Mark Stockdale says it's impossible to predict whether it will succeed.
"It just remains to be seen that once these legislative changes are made that it will increase competition and [whether] that will in turn lead to lower prices," Stockdale told Newshub. "The proof will be in the pudding."
Instead of just displaying 91 octane and diesel, the proposed Bill may see stations required to display all prices.
Stockdale said that's bound to make a difference to the price of premium petrol, which often isn't displayed, but could be the only significant change at the pump in the coming months.
Minister for Energy Megan Woods said on Thursday the Government was taking swift action to ensure there's a fair and competitive market that works in the interest of consumers.
But Steven Summers from Business New Zealand told Newshub he hopes investigations into petrol pricing don't become common practice.
"We'd be concerned if there was an annual event regarding market studies," he said. "Each one needs to be warranted in itself before these investigations take place."
Summers said fuel companies were forced at great cost to participate in the Government's market research. A Commerce Commission report found New Zealanders were paying too much for petrol.
"These studies involve significant compliance costs," Summers said. "You have the provision of substantial information that participants have to provide and also a lot of internal time taken by staff."