Relief on a timer
The numbers look good at first glance. Brent crude dropped about 16% to US$92 per barrel after Washington and Tehran announced a ceasefire, while West Texas Intermediate fell almost 20%. Asian equity markets surged. The S&P 500 posted its strongest weekly gain since November. Traders were, as Pepperstone’s Michael Brown put it, “desperate for good news”.
But desperation is not analysis. Before the conflict, Brent sat at around US$65-70. At US$92, it remains roughly 35% above pre-war levels. Saudi officials had warned prices could exceed US$180 by end of April without a ceasefire, so the deal averted catastrophe. It did not restore normality.
And the deal itself is a two-week halt to attacks built around a “workable” 10-point proposal from Trump. Not a peace agreement. Not even close.
Why NZ pump prices will barely move
New Zealand does not refine crude. Z Energy and other importers buy refined fuel on international markets, so a crude price drop does not translate directly or quickly to the pump.
Then there is what Infometrics chief forecaster Gareth Kiernan calls the “air bubble” – a month-long lag as physical supply works through the system. The Strait of Hormuz normally handles around 125 ships per day. During the conflict, it was running at about four. Reopening a shipping lane is not the same as restoring flow.
The biggest constraint is refining margins. Kiernan warned that Asian crack spreads are still increasing, likely pushing diesel past $4 per litre in the near term regardless of what crude does. Finance Minister Nicola Willis confirmed the dynamic: “Refineries had an extended disruption to crude supplies, so it could take extra time to flow through to lower prices for petrol and diesel.”
The most optimistic credible estimate comes from Westpac chief economist Kelly Eckhold, who suggested the drop could be consistent with petrol falling about 20 cents to roughly $3.30 per litre for 91 octane, but only if conditions hold for several days. The AA’s Terry Collins was blunter: a more sustained move to end the conflict would be needed before NZ motorists saw real relief.
The inflation damage is already baked in
This is the angle most commentary is missing. Even if oil normalises tomorrow, the monetary consequences of the past five weeks are locked into the system.
Diesel prices rose 38% and petrol 17% since the conflict began. Swap rates climbed over 70 basis points between 2 and 23 March, pushing up bank funding costs and flowing directly into retail mortgage rates. The Reserve Bank now forecasts inflation of 3% for the March quarter and 4.2% for June, while holding the OCR at 2.25%. ANZ is calling for as many as three OCR hikes over the remainder of the year.
As Prime Minister Luxon acknowledged: “There’s no escaping the fact there will be a hit to inflation and economic growth, and that means real impacts for Kiwis beyond the price of petrol.”
Who carries the heaviest load
Infometrics data makes the sectoral exposure stark. New Zealand consumed 47.2 million barrels of oil products in 2025, with diesel accounting for 51%. Domestic transport used 77% of all diesel consumed, and transport operators carry 19-26% of non-wage operating costs in fuel. Fishing and aquaculture is the single most exposed sector at 26%. Agriculture, horticulture, and commercial services all face meaningful cost uplift.
Beyond fuel, petrochemical feedstock disruption has pushed plastics prices sharply higher, hitting manufacturers, packagers, and construction firms.
Don’t unwind the hedges yet
As of 5 April, New Zealand had 62.6 days of petrol supply in-country or on ships in transit. The Commerce Commission is watching whether crude drops flow through to retail prices, noting that costs rose faster than pump prices on the way up.
Businesses that renegotiated contracts, locked in fuel hedges, or restructured operations during the crisis should hold those positions. A two-week ceasefire with no underlying resolution, combined with inflation forecasts that have already shifted the interest rate outlook, is not a signal to return to business as usual. It is a signal that the cost base has moved, and the question is how far it settles, not whether it snaps back.
Sources
- RNZ: Oil prices fall, will petrol follow? (2026-04-08)
- NZ Herald: PM Christopher Luxon cautious over proposed US-Iran ceasefire (2026-04-08)
- 1News: Global oil prices fall – how long until NZ’s petrol and diesel follow? (2026-04-08)
- Newstalk ZB: Crude prices plunge, stocks surge as US and Iran agree ceasefire (2026-04-07)
- NZ Herald: Markets rebound but oil shock tests how long the resilience can last – Generate Wealth Weekly (2026-04-07)
- MFAT: Weekly Global Economic Report – 17 March 2026 (2026-03-17)
- MFAT: Weekly Global Economic Report – 23 March 2026 (2026-03-23)
- MFAT: Weekly Global Economic Report – 31 March 2026 (2026-03-31)
- Infometrics: Oil shock a challenge to industrial New Zealand (2026-03)
- RNZ: Luxon, Willis caution economic effects will continue despite ceasefire (2026-04-08)
- Commerce Commission: Fuel price monitoring (2026-04)