The Marlborough District Council receives more complaints for "ugly" tiny houses than it does resource consents for them.
This prompted council to draw up a pamphlet after the number of small dwellings caught floating building consents rose in the region.
It detailed when a building consent was required and the implications not having consent could have on tiny house owners, to prevent them facing unexpected costs when neighbours turned them over to authorities.
Council advocacy and practice integration manager Barbara Mead, who compiled the pamphlet, said people often called to criticise "that ugly thing over there" or the new "second dwelling" overlooking their garden.
"That's commonly a trigger point, or it could be also a genuine concern around the safety of the home ... They haven't necessary thought about whether or not it [the tiny home] is lawful. That's why they ring you," she said.
Tiny homes included converted containers, purpose-built constructions and converted out-buildings, such as sheds. Tiny house owners in Marlborough either sought a "simplified" lifestyle or an affordable solution to housing.
But council building control group manager Bill East said compliance officers had seen some "shockers" over the years, with six ordered to be brought up to regulation last year alone after complaints.
A common reason tiny home builders avoided building approval was the current building act made it "quite problematic" to prove compliance, he said.
"But this is also about the Kiwi handyman who thinks he can just get a container and whack a window in it and say, 'I've got a house'."
Mead said confusion on whether the buildings needed consents was also a factor, as people thought buying a tiny house was like buying a caravan.
"That's where our education needs to be focused," she said.
The Ministry of Business, Innovation and Employment (MBIE) often ruled immoveable dwellings were buildings, and subject to building consents, but were debating whether small, movable dwellings were buildings or a vehicle.
The pamphlet said accommodation dubbed a 'vehicle' could still need a building consent if the owner wanted water, drainage or power, or a resource consent for vegetative clearance, water or construction near a riverbed.
East said information was compiled from the Resource Management Act, the Building Act, and Building Code advice from MBIE determinations.
"The ramifications of getting one of these structures appears to be really simple. Grab it, pick it up, put it on your site. But actually, because of the law, it isn't. There's huge amount of considerations to be made," East said.
Education was the council's first port of call once a building without consent was found, but this could escalate depending on the severity of the tiny home's non-compliance, with prosecution being the "end level", he said.
East said the council tried to avoid putting undue bills and stress on people who could have invested "everything they've got" into the smaller house.
The council last year fined a builder $8500 for building five "small dwellings" on his Blenheim property and connecting them to a wastewater system.
Mead said the pamphlet could have been used as part of the council's prosecution if it had of been available at time, as evidence of attempts to educate, but she wasn't sure how this might have affected the outcome.
The council would soon attend a hearing about a tiny house on wheels with MBIE, who decided the council's notice to fix was inadequate, and Eco Cottages, who built and supplied the tiny home. A date had not yet been set.
The pamphlet would be amended if the hearing impacted council advice.
Mead said it was likely changes would be made to the building act to accommodate pre-built tiny homes which hadn't been built for a specific site.
"You can't predict these things ... [and] whether that innovation is dealt with by those producers or by consumers or by councils, we're unsure," she said.
Kaikōura boasted a shipping container mall on its main street, and Vines Village's Elemental Distillers worked from a converted container. A tiny restaurant was pitched for Picton's foreshore last year, but later declined.
The pamphlet was available on the council's website.