The average price of 91 unleaded petrol in New Zealand reached $3.25 a litre on Friday, and the Automobile Association says motorists should not expect much relief before Christmas.

The figure comes from the fuel price app Gaspy, which showed petrol up nearly 25 cents a litre over the past 28 days.

It is the highest average since late May, RNZ reported.

Diesel averaged $2.96 a litre on Gaspy, still well short of the peak of about $3.80 it reached in April.

The AA expects high prices to last at least another six weeks, and possibly until mid-November.

AA principal policy advisor Terry Collins was blunter about the longer outlook.

“We probably won’t get much relief before Christmas, unless something really major happens geopolitically,” he told RNZ.

Global crude oil has climbed back above US$100 a barrel in recent weeks as supplies from key Middle East producers remain constrained by the conflict between the United States and Iran.

Collins listed restricted supplies through the Strait of Hormuz, attacks on Saudi oil pipelines, soaring insurance costs for oil tankers and a lower New Zealand dollar as the forces pushing prices up.

He also pointed to the United States midterm elections on 3 November as a reason the pressure may not ease soon.

Collins suggested Iran has an incentive to keep oil tight until American voters go to the polls.

“They’ve got no military might that they can attack the USA.

But what they can do is make them pay through the ballot box by forcing up the price of diesel,” he said.

Official figures tell the same story, a week behind.

The Ministry of Business, Innovation and Employment’s weekly fuel price monitoring data put the national average board price for regular petrol at 306 cents a litre in the week to 11 September, up from 300.5 cents a week earlier.

A year ago the same measure was 260 cents.

MBIE’s board price is a different measure from Gaspy’s user-reported average, so the two numbers do not match exactly, but both are moving the same way.

The crude price is the main driver.

MBIE’s benchmark Dubai crude averaged US$109 a barrel that week, against US$70 a year earlier.

With the New Zealand dollar buying just 58.5 US cents, that works out at NZ$187 a barrel, up from NZ$118 in September 2025.

A weaker currency makes every barrel dearer for importers, even when the world price holds still.

Diesel has risen even faster over the year.

MBIE’s average diesel board price was 275 cents a litre in the week to 11 September, compared with 190 cents a year earlier, a rise of roughly 45 percent.

Petrol is up about 18 percent on the same comparison.