The taxpayer has paid potentially millions of dollars in free renovations to private homeowners as a result of Housing New Zealand's botched campaign against methamphetamine contamination.

Around five percent of Housing New Zealand's stock is leased from private owners, but the agency still paid for methamphetamine decontamination repair work for many of these properties.

Because most of that work was unnecessary, Housing New Zealand (HNZ) essentially used taxpayer money to renovate private homes.

Photo: RNZ / Claire Eastham-Farrelly

One example is charity Accessible Properties, a subsidiary of IHC, which bought 1142 state homes in Tauranga last year - most of the city's stock.

As part of that sale, HNZ agreed to pay for any methamphetamine decontamination work required on those homes, despite selling them below market value.

Accessible Properties identified 147 homes that needed decontaminating, and, according to a HNZ contractor who spoke to Checkpoint, started capitalising on those repairs that were being paid for by HNZ.

"Some houses we will go into we will have a job sheet, one under HNZ, and one under [Accessible Properties], because HNZ is paying for all the [decontamination] work, but [Accessible Properties] might go, oh yeah, okay, paint that lounge, and let's fix that up too," the contractor said.

"In a sense, Accessible Properties got an upgrade of 147 properties, which is not cheap," Otago University public health professor Philippa Howden-Chapman said.

The $100 million HNZ spent on methamphetamine decontamination across the country could have been spent on building close to 200 new state homes, she said.

“That would’ve meant we wouldn’t have this cascade of housing problems, both for the people who were in the houses, and also for the fact that there’s a big gap in the number of state houses that were built."

Accessible Properties chief executive Greg Orchard declined to be interviewed, as did HNZ chief executive Andrew McKenzie.

In a written statement, HNZ said meth decontaminations "were, and will still be, done for the safety of tenants".

"Just because a new standard is coming it is wrong to say that houses were 'needlessly being de-contaminated' when that work was undertaken according to the previous standard," the statement said.

HNZ would continue to test houses where it suspected there had been meth lab activity or heavy meth use, and decontaminate properties that exceeded the higher standard of 15 micrograms per square metre, it said.

Accessible Properties said it would continue decontamination work on 42 properties in Tauranga that are currently being decontaminated, despite it being highly likely none of those 42 need the work done.

Housing New Zealand will pay for that continued decontamination work.