Iran war: No relief on the horizon as diesel hits $3.44, overtakes petrol price
Monday, 30 March 2026
Diesel is on average now more expensive than 91 octane petrol at the pump, according to price comparison site Gaspy.
There appears no relief for fuel users on the horizon, with oil prices rising further when global markets reopened on Monday amid speculation of the United States launching a ground war in Iran.
Brent crude was trading at just over US$108 a barrel shortly before 1pm, up US$3 on its pre-weekend close.
Gaspy first reported diesel prices had overtaken petrol on Sunday afternoon.
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At lunchtime on Monday it was quoting the average price of diesel at a fraction of a cent under $3.44 a litre, and 91 a fraction of a cent under $3.43.
Road User Charges add the equivalent of about 80 cents a litre to the price of diesel, meaning it is now far more expensive on a per-kilometre-travelled basis.
The latest data published by the Australian Institute of Petroleum on the cost of importing refined fuels from Asia suggests the diesel price rise has been justified.
The Singaporean benchmark for diesel rose to a new high of just under A$350 a barrel on Friday, up from A$130 a barrel before the conflict, it reported.
That equates to a rise of NZ$1.65 a litre, excluding GST, from the pre-conflict price.
Higher refining margins relative to petrol, lower fuel stockpiles, easier hoarding, and its lower price elasticity of demand are all reasons why diesel tends to rise in price at a faster price than petrol in a supply crunch.
Diesel has emerged as probably the weakest link in the fuel supply chain in the wake of the conflict in the Middle East.