A new report has found there's evidence to believe petrol prices are unreasonable.
Megan Woods, the Minister for Energy and Resources, says she's had enough of petrol companies ripping off motorists.
The Government will fast-track work to allow the Commerce Commission to undertake a market study.
It follows the release of a fuel market study update, which shows over the last nine years, New Zealand has gone from having some of the lowest pre-tax fuel prices in the OECD to the highest.
"The report highlights concerns about the price Kiwis are paying at the pump," Dr Woods said.
"This was based on the rising levels of importer margins since 2008 and a rising spread of retail prices between Wellington and the South Island and the rest of the North Island.
"MBIE notes that the rise in margins since 2008 represents a transfer of wealth from consumers to producers to the tune of hundreds of millions of dollars."
Retail gross margins have increased by 13 cents per litre over five years, with Wellington and the South Island feeling the sting the most.
Ministry of Business, Innovation and Employment (MBIE) officials will continue to monitor the market and explore options for regulatory interventions.