A Masterton trucker is pulling half a dozen rigs off the road at a cost of $10,000 a day to comply with a new and urgent safety alert.
The Transport Agency's warning, covering almost 500 heavy vehicles, marks the second wave of costly disruption to hit the industry this year.
About 1500 heavy vehicles had already been forced off the road entirely in April - and more than half of those are still off the road as the backlog puts huge pressure on overworked certifiers to do reinspections.
The latest safety alert demands that operators clean and check towing connections for cracks.
This follows an investigation into Wellington certifier Dick Joyce, who has been suspended since June. It found towing connections were either too old or too weak for the loads they were pulling.
"We've gone through 156 files, there's 480 files all up, and we've determined there is an issue, that the towing connections are certified to a higher weight than they've been designed to cope with," Craig Basher, of the Transport Agency, said.
"So you can get a towing connection failure, the fatigue life of the towing connection is less because it's subject to more stress, and you can get cracks."
The 483 vehicles include heavy haulers and logging trailers.
Graeme Reisima runs a dozen trucks with Reisima Haulage in Masterton, and half his fleet has been hit.
He won't let them tow anything until the local workshop's made sure they're OK, though cutting his payload of hay and timber by half will cost him $10,000 a day.
"The trucks that were planned to go to work tomorrow, can't go to work.
"We've washed them and looked at them and, really, we'd want to take it down the engineers and say, 'can you run your eye over this just to make sure it's 100 percent safe'," Mr Reisima said.
"None of us want to be driving something that could be dangerous - we don't think we are - but you want to err on the side of caution."
'He over-engineered stuff and was risk-averse'
Mr Reisima was surprised Mr Joyce has become the second certifier, after Nelson's Peter Wastney, to fall foul of the agency.
He had not seen anything wrong with his own trucks, not heard of worries from other truckers before now, and had not heard of any actual failures.
"I've known him for 15 years. I thought he was extra-cautious, he over-engineered stuff and was risk-averse, so I'm very surprised at this."
Mr Joyce told RNZ he wanted time to look at the safety alert before commenting.
Mr Basher, from the Transport Agency, defended the time it took the agency to issue the safety alert, given it was an audit in May 2017 that raised alarms about Mr Joyce. The agency had tried to get him to improve, he said.
"The issue we worked through ... hasn't resulted in the results we were looking for."
Mr Reisima said the Transport Agency should bear the costs related to Mr Joyce, but the agency has only said that it had no liability and was considering the options.
"If they're going to accept some liability for the lack of auditing which allowed that to occur with Wastney, they're going to have to accept the same responsibility with Dick Joyce."
The agency for years has had just one auditor to cover all 180 certifiers nationwide. Now it is recruiting three more, and two engineers.
It is also bearing millions of dollars of costs in the Peter Wastney case.
Mr Reisima had one Wastney-certified truck and the agency picked up a $1000 bill to recertify it.
He was "horrified" to learn that 848 Wastney-certified vehicles were still off the road, 15 weeks after their certifications were revoked.