Motorists in many parts of the country have been hit by the third petrol price increase in a week.

Stations in central Wellington and many parts of the South Island show regular petrol is now $2.129 a litre, marking a 9c a litre rise in eight days. The increase was in place on Tuesday evening.

The so-called “main port” price is now at the highest level since November 2014. The pricing, used widely in Wellington, the South Island and pockets of the upper North Island where there is no regional discounting, peaked at $2.269 in 2013, according to data collected by the AA.

While petrol companies have partly blamed a sinking New Zealand dollar for the recent increases, the kiwi is marginally stronger now than it was on October 30.

The New Zealand dollar plunged following the September 23 election, with much of the fall coming when Winston Peters announced he was forming a Government with Labour, and again when NZ First and Labour published a coalition agreement.

But through the initial drop, petrol prices remained steady, with figures from the Ministry of Business, Innovation and Employment showing the margins petrol companies are estimated to be making dropped by about 7 cents a litre through the fall, to below what has been normal since 2014.

Meanwhile crude oil prices rose to a two-year high, blamed on concerns about stability in Saudi Arabia.

Petrol prices have gained increased scrutiny this year after a Government-ordered inquiry questioned whether the market was competitive, and said margins had risen in recent years which was not justified by increased investment.

The refusal by Gull and Mobil to provide the inquiry with the information it was seeking – despite personal requests to both companies from Energy Minister Judith Collins – was one of the reasons the former National-led government recommended the Commerce Commission be granted additional powers to conduct market studies without having to have evidence of collusion.

Extracted from: Stuff