Petrol prices fall as quickly as they rise, according to a new report out yesterday from the New Zealand Institute of Economic Research.
Commissioned by Z Energy, the NZIER report found petrol companies passed on oil price decreases to consumers just as quickly as they passed on increases in price.
NZIER analyst John Stephenson said the same result was found when NZIER analysed prices in 2013.
''Our analysis also shows that the speed at which oil price changes end up in retail prices - both ups and downs - has accelerated and become more volatile. From a consumer perspective, these dynamics are positive. These results suggest competition has become more robust.''
Z chief executive Mike Bennetts said the company understood there was a high level of public interest concerning fuel pricing and believed its customers and stakeholders deserved impartial and independent facts on the matter.
However, Mr Bennetts strongly emphasised Z had no input into, or review, of the report before its publication.
''We felt it was important there were facts in the public discussion around fuel pricing.''
In the past 12 months, there had been the most sustained and vigorous competition in fuel markets in Z's five-year history as a local company, he said.
Consumers reading the report could be assured the market was highly competitive and that fuel prices rose at the same speed as they fell.
A further reference point for consumers and stakeholders would be Z's annual result to be released on May 7.
The company would release detailed analysis concerning its profitability and performance, Mr Bennetts said.
In his report, Mr Stephenson said at first glance it appeared changes in oil prices were passed through to petrol prices relatively quickly.
But whether the price response to increases in costs was the same response as decreases in costs - the New Zealand price of Dubai crude - was not immediately obvious.
''We ran the numbers and found no evidence of opportunistic gouging. We found that petrol companies pass on oil price decreases to consumers just as quickly as they pass on increases in prices.''
Prices had gone up and down at the same speed for at least the past decade, he said.
But Mr Stephenson also found price change pass-through had become more rapid in the past three years.
That meant both oil price reductions and oil price increases ended up in retail prices more quickly than they used to.
