Many of the nation's baby boomers are selling their baches in exchange for a motor home or caravan - but a sting in the tail has prompted a $50,000 consumer warning.
The Plumbers, Gasfitters and Drainlayers Board (PGDB) has reported an upsurge in complaints about unauthorised gasfitting of motor homes, camper vans and caravans.
PGDB chief executive Martin Sawyers says complaints increased in the 2016/17 year, compared to the previous year - and says the increase in people with motor homes has seen a corresponding rise in gasfitting problems.
One example concerned a man fined $5000 earlier this year; he did not hold a gasfitting licence when he installed a refrigerator and gas pipes, connected the pipes to the gas supply and installed a ventilation system for the gas appliance in a motorhome.
His work created a substantial risk the fridge would overheat and fail - and it did so - and it created a risk of a gas leak, in turn creating a risk that a fire or explosion could result.
Bruce Lochore, chief executive of the New Zealand Motor Caravan Association, says there is no doubt motor home, camper van and caravan numbers are increasing on New Zealand roads.
"We now have 74,000 members," he says, "and over the last two years we have grown by 14,000 and by 10,000 for the two years before that."
That is effectively 50 per cent growth in four years; Lochore says it is being spurred by retired baby boomers selling up baches in exchange for a cheaper, more mobile holiday experience. People in their 50s, still working, were also buying camper vans and similar vehicles before retirement. Young families were the third echelon of growth, many buying caravans.
"Maybe the best illustration of growth is the Covi Show, the major show of the industry, held every year at the ASB showgrounds. Last year, they sold $18m-$19m of motor homes and caravans," he says. "This year, it swelled to $30m."
Sawyers says the upswell in motorhome numbers brings with it a problem, especially for those who buy a used campervan or motorhome where gasfitting has already been done.
"If the fitting has not been done by a licensed professional, it is a problem which passes on to the new owner," he says. "The danger level there means it could be expressed as a ticking time bomb if the work is defective.
As of 2013, a certifying gasfitter must provide a signed certificate if restricted work has been carried out in a scenario like a motor home. Consumers should ensure, says Sawyers, the certificate is passed on at the time of sale - and keep it somewhere safe.
"It might be needed for insurance purposes or if the motor home is re-sold. That's what we say in all our warnings on this subject - the $50,000 maximum fine is so heavy because gas is such a tricky thing to deal with and the dangers are real."
If there is no gas certificate available, consumers should contact a certified gasfitter who can issue a certificate of verification for the safety of the existing installation.
Another motor home example concerned an unauthorised workman who installed an LPG refrigerator and a flue in a motor home. The work was judged defective by a registered gasfitter, called when the owner of the motor home noticed a bad smell coming from the refrigerator that had made her feel ill and light-headed.
The gasfitter considered the defect to be immediately dangerous to life - and reported it, with the unauthorised tradesman later convicted and fined $4000.
Lochore says: "It is a dangerous risk; we always encourage our members to go to a licensed gasfitter and refer them to a website where they can find them."
Sawyers says the PDGB are seeing increased numbers of "cowboys" going to court "because we are getting better at detecting them."
The Report A Cowboy (RAC) app launched last year, downloadable from the PGDB website, had attracted more than 10,000 downloads - with 126 complaints laid over the app last year with 15 so far this year. Just under half the complaints involved allegedly unauthorised plumbers.
The PGDB's awareness programme, "Sort the pros from the cons", had also helped make homeowners and landlords realise they had only to ask for a registered tradesman to produce a licence card issued by the PDGB to be sure they were dealing with a bona fide professional.
"Keep safe and avoid dealing with any service providers who cannot produce a licence card issued by the PGDB," he says, "and if you have any suspicions or want to report some alleged wrongdoing, use the RAC.