A refresher on fuel measurement and sources

Fuel is critical to the New Zealand economy, enabling goods and people to move around. With fuel needing to be imported into New Zealand from overseas, the source of our fuel, and the wider refining supply chain, are important to consider, as is the local pricing trends here at home.

With some changes to fuel price monitoring in New Zealand, we thought it worth putting together a brief recap on some of the terms used and what they measure, how the revisions have changed fuel price trends, and highlighting the change in where New Zealand gets its fuel from.

Our regular reporting on fuel prices, including in our forecasts, are based on analysis of data provided by MBIE. This reporting from MBIE has a range of measures, across 91 regular petrol, 95 premium fuel, and diesel, including:

• The board price – the national average advertised price (on fuel board at service stations).
• The discounted price – sometimes quoted as the “adjusted retail price”, is the national average price paid by consumers once discounts (like loyalty programmes that offer lower per-litre prices) and other factors like vouchers and regional variations “not accounted for in [MBIE’s] aggregation methods” are included.
• The importer cost – the calculated cost of purchasing the fuel and importing it to New Zealand. Base prices are constructed from Singapore fuel spot prices, and then additions are made for shipping and wharfage (based on figures from Envisory and Argus Media).
• The importer margin – the discounted (retail) price less direct taxes and levies, GST, ETS, and the importer cost.

Our practice at Infometrics is to report on the discounted price, as it is likely to be closest to what motorists actually pay for fuel.

MBIE have recently updated their methodology, and published revisions to history since 2022 for their fuel series. We will incorporate these revisions into our reporting in our next forecast round, but have been examining the differences in the meantime.

The new approach includes a more robust approach to measuring retail board prices, using data from Gaspy (provided by Datamine) as reported by motorists across regions, and then aggregated to a national average, weighted by regional population shares.

The discounted price is calculated as the difference between the quarterly average retail price and the Stats NZ consumers price index (CPI) quarterly average value of the price paid for fuel (rather than price advertised). This difference (presumably on a percentage basis) is then applied to the weekly retail board prices, to construct the discounted price series.

On a quarterly basis, which is what we usually report, fuel prices have seen some reasonable revisions since 2022 under the new MBIE methodology. Revisions have occurred for both the board price, and the discounted price. At their largest, the changes range from a difference of 16c/L lower than originally reported, to 13c/L higher than originally reported.

The new series has more difference with the old series over 2024 and into 2025, with the news series showing less jolty movements in fuel prices week-to-week. The new series is materially lower than the old series from June 2024 to February 2025, by over 10c/L for the board price of 91 regular petrol.

Recent international visits also highlighted a shift in where New Zealand sources fuel from. The 2022 closure of the Marsden Point oil refinery and conversion to an import supply operation in Northland has changed what fuel New Zealand brings into the country, and where it’s from.

As Chart 3 shows, Korea now provides the largest value of fuel imports into New Zealand, contributing 48% of the value of fuel imported over the 12 months to March 2025. Singapore was the second largest source, contributing 33% of total fuel imported.

The source of New Zealand’s fuel has shifted substantially over time. The shift since 2022 has been driven by the closure of Marsden Point, which previously refined the majority of New Zealand’s fuel. Before then, New Zealand imported a mix of unrefined crude (usually direct from oil producing nations) and refined fuel.

The shift in 2022 shows that, previously, a large volume of unrefined crude from the UAE was imported and refined at Marsden Point, which was replaced with fuel from refineries in Singapore and Korea. Both countries import unrefined crude from across the Middle East, but in particular Saudi Arabia and the UAE.

Previously, Australia and Saudi Arabia were key importers of fuel to New Zealand – the former for refined fuel and the latter for unrefined oil. Other important import partners over time (captured in the “All others” group) include Taiwan, Qatar, Indonesia, and Brunei Darussalam.