An independent study commissioned by the Government has cleared petrol companies of allegations they are quick to increase but slow to cut domestic petrol prices.
Commerce Minister Lianne Dalziel says the report has found the petrol market in New Zealand is fundamentally competitive.
She says perceptions that petrol prices are quick to rise but slow to fall are just that - perceptions.
The report confirms the rising cost of crude oil overseas has been largely responsible for price rises in New Zealand.
Ms Dalziel says the report makes clear there would be no benefit in introducing a Fuelwatch scheme similar to one in operation in Australia.
However, she says more openness about petrol importers' profits would be useful for motorists, and officials are working on providing better information.
The report found New Zealand has the fifth-lowest petrol prices - including taxes - in the OECD.
The Automobile Association says the results of the independent study give confidence to motorists.
AA spokesperson Mike Noon says the findings reassure his organisation that fuel companies are not operating as a cartel.
Mr Noon says the report supports increased competition and monitoring, and the association will keep an eye on that.