The New Zealand Initiative has raised the hackles of many with its report claiming increased workplace safety is one of the reasons for the lack of affordable housing in Auckland and Christchurch.
The research institute says the workplace safety is costing Kiwi homeowners $100 million a year.
But Council of Trade Unions president Helen Kelly said in an interview the credibility of the NZ Initiative had been ''shot to pieces'' by the release of the politically motivated report.
''Just one week before the select committee meets, every dog whistler in the country is getting behind the Government, which is already trying to water down the legislation.
''I hope they get broken bones in the mail.''
Large construction companies had been unaccountable for workplace safety until recently, she said. They were now placing their support behind the campaign to lift workplace safety standards.
TheA Matter of Balance: Regulating safety report claims a ''Falls from Height'' workplace safety campaign from WorkSafe New Zealand is adding thousands of dollars to the cost of building new homes and routine maintenance of homes, without proper justification.
The institute claimed WorkSafe was part of the Ministry of Business, Innovation and Enterprise when it is a stand-alone crown entity.
WorkSafe and Graham Burke, the president of the New Zealand Specialists Trade Contractors Federation, contacted the Otago Daily Times to take issue with the report.
Mr Burke said the report presented a ''very one-sided view''. The new falls from height programme had significantly reduced accidents among people working on houses.
Most of his members were owners of small and medium-sized enterprises and were the last people wanting more red tape. But they realised something had to be done.
The federation was working with WorkSafe to keep the compliance costs to a minimum while recognising the importance of the rules.
''As a home owner, who wants to look at the spot where the roofer fell off?'' he said.
WorkSafe chief executive Gordon MacDonald said falls from height had been targeted because they were a significant cause of injuries and fatalities in construction.
The costings in the NZ Initiative's report were largely based on anecdotal information from a few builders, he said. The cost of installing safe work systems for a single-storey home to prevent falls from a height ranged from about $2000 to $4000. Scaffolding could be bought for about $12,000, meaning it would pay for itself after six to eight builds.
WorkSafe data showed there had been a 29.5% reduction in notifications of serious harm caused by falling from a height between 2012 and 2014.
That meant 21 fewer people suffered serious injuries froma fall in the construction sector in 2014 compared with 2012,Mr MacDonald said.
Executive director of the NZ Initiative Oliver Hartwich said workplace safety was a hugely important issue. However, further increasing the cost of routine maintenance and building through unnecessary regulation was a major public policy concern and should not continue.
The campaign particularly targeted workplace falls of less than 3 metres, which potentially affected all single-storey homes. Critically, no official cost-benefit analysis was carried out before the campaign was rolled out, he said.
Primesite Homes director Mike Fox said the current obsession the authorities had with trying to prevent falls from heights on residential projects was costing the nation, both financially and in lost productivity.
''In my experience, the cost to homeowners of the current approach is up to $15,000 per new single-storey dwelling.''
The new regulations also dramatically increased the cost of necessary home maintenance, he said.
The report claimed a small-scale builder reported the cost of complying with the WorkSafe New Zealand campaigned turned a small $4000 roof job into a $6000 job.
Dr Hartwich said if half of New Zealand's 1.8 million single-storey dwellings needed a new roof every 12 years, at an additional cost of $2000, the annual additional cost burden on householders of roofing alone was $150 million.
''These additional compliance costs may induce some homeowners to further defer necessary maintenance work and take greater `do-it-yourself' risks.''
Ms Kelly said the report had assumed all of the costs up front, when companies buying scaffolding would use the equipment across many years.
