A Palmerston North coachbuilder who helped raise the alarm over truck cab cutouts warns he is finding motorhome cabs that are a threat to road safety.
The Transport Agency Waka Kotahi is enforcing a rule on modifications to truck cabs that has forced some motorhomes and horse trucks off the road.
Coachwork Central has had four motorhomes brought to it which had been rejected for a Certificate of Fitness since the clampdown began in April.
Director Neil Alexander said his firm is stripping them back and finding some modifications - usually cutouts that allow access to the accommodation in the rear - have made cabs too weak.
"Some of the especially imported cabs that we've taken to pieces, underneath the shiny exterior some of the workmanship and actual engineering is poor to say the very least," Alexander said.
"The cab has actually got not much structure holding it together."
This could be the case even when the interior trim was flash, he said.
"I've actually got one which is sitting in my back yard right now where the owner has actually scrapped the job, it was so badly done."
The clampdown was justified if a cab was badly done but there was no way to tell without stripping a cab back, which could be painstaking work, Alexander said.
He expected thousands of vehicles will need checking.
It was costing about $10,000 per motorhome and taking four or five weeks, even for good cabs that did not need repairs, as they still needed to prove they met the requirements for LT400 certification, he said.
Some owners struggled just to find an engineer willing to take a look.
Alexander was involved in tests done on modified truck cabs in 2018 by certifying engineer David Manley that led to Waka Kotahi moving to enforce the rules.
The agency said the rules had been there for years but it had been giving "ambiguous" information to inspection agents.
Alexander helped raise the alarm in 2018, but denied any conflict of interest over now benefiting from rectifying the problems.
"It's just the way it's worked out,"he said.
"I'm really doing it because we're just willing to help people out.
"Our type of work's drying up a bit and it's a niche that we can do, and do well for people."
Waka Kotahi says it was working with the industry to simplify a difficult inspection-and-fix process.
Alexander said he did not see a resolution in sight. He added that Manley was working with NZTA on this.
Manley declined to comment.
"If tomorrow they change the rule and simplify the process for people, and they don't have to pay so much money, that's fine," Alexander said." And good luck to them. But at the present point in time, we can help out."
He expected tourism operators would not be affected, as those he knew of had the correct LT400 signoffs for any cab modifications.
Two operators who run truck-bus tours on 90-mile Beach and Farewell Spit told RNZ they were not aware of the clampdown.
Tourism Industry Aotearoa was not aware of any concerns.