Iran war: Call to change truck weight limits as diesel price tops $3.80 a litre
Wednesday, 8 April 2026
The Government could ease some trucking regulations later this week to enable more freight to be transported with less diesel, the National Road Carriers Association believes.
“At a time like this, you’re looking at every possible thing you can do,” policy manager James Smith said.
But he cautioned any easing of regulations would only help at the margins, given there were practical limits to what could sensibly be done quickly.
Globally the trend is towards heavier trucks, but the number and condition of New Zealand’s road bridges could be a handbrake here, he warned.
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Fellow industry body Transporting NZ called last week for regulations to be “urgently amended” to allow some trucks to carry heavier payloads in the light of the rising price of diesel.
Price comparison site Gaspy reported on Wednesday morning that the average price of diesel had now reached $3.81 a litre, more than double its price before the start of the Iran conflict.
Transporting NZ chief executive Dom Kalasih advocated for the weight limit on nine-axle “50Max trucks” and other so-called High Productivity Motor Vehicles (HPMVs) to be raised.
50Max trucks are currently allowed to have a loaded weight of up to 50 tonnes but, like other HPMVs, they are only allowed to travel on some parts of the roading network.
“HPMVs are already delivering fuel savings compared to standard 44-tonne trucks. For example, 50Max trucks increase freight capacity by approximately 20% while only increasing diesel use by 10%, with their additional axle ensuring no additional wear on roads per tonne of freight,” Kalasih said.
A spokesperson for the Ministry of Transport said officials had met with “heavy vehicle industry representatives to understand regulatory barriers and identify potential changes” and that ministers were expected to consider initial advice from officials shortly.
A Transport Agency (NZTA) spokesperson said it was separately exploring what could be done within the current rules to reduce pressure on freight costs “without compromising road safety or damaging the state highway network”.
Kalasih said Transporting NZ was ever hopeful of rule changes “but it was all a guessing game”.
Smith said truck weight limits had been under review for 18 months, in part because of an international trend towards manufacturers making heavier vehicles, including electrically-powered trucks.
“Electric trucks are generally heavier, unless you want to start leaving payload behind.”
The Middle East conflict had added a sense of urgency to the review underway, he said.
“The Government could probably allow some trucks to carry more weight on certain roads at very low risk.”
But there were complications to speeding up the policy work, he said.
One was that New Zealand had “the highest bridge count per 100 kilometres of road of just about anywhere in the world”, in different states of repair, he said.
Many of those bridges were approaching 100 years old and, if they were on more minor roads that were under the jurisdiction of a local council rather than the NZTA, they might not have been visited by an engineer recently, he said.
“It’s a concern not just for road transport. Our friends at KiwiRail are also facing a similar challenge with their bridges.
“There is an HPMV network, but it doesn’t go everywhere.”
Weight was not always the restriction on how much cargo trucks could carry, Smith said.
The amount of food that trucks could carry was more commonly limited by the volume of freight they could accommodate, for example.
Smaller changes that could save some operators fuel could include easing restrictions on oversized trucks travelling on motorways and toll roads, he said.
Trucking Association chief executive David Boyce agreed any consideration of weight-limit changes would “need to look at the whole picture”, including “the wear on the roads and safety limits”.
Kalasih said the risk to bridges already existed and he believed any extra risk caused by rule relaxations could be managed.
“There are lots of bridges that cannot take certain weights, but there are risk controls in place to manage that. There’ll be a sign up to say ‘this bridge is limited to this weight’, so given that there is already a good system to manage that, we shouldn’t be saying, ‘let’s not do anything because there’s this risk’.
“No transport operator wants to operate unsafely. You’re not going to go over a bridge if they think their million-dollar truck is going to fall through it,” he said.