The testing and cleaning of meth-contaminated properties is a ''cowboy industry'' with some operators accused of preying on people's fears.
Consumer New Zealand, rental managers and established testing companies have today hit out with concerns the industry nationally is too unregulated and say changes are needed.
One local expert estimates there could be dozens of rogue operators across the country.
A new national standard around P-contamination testing and clean-up is expected to be introduced next month -- but it would be voluntary. However, the Government has plans to make the standard law in future.
BOP Rentals owner Gary Prentice said his company had one rental house tested four times by different businesses with different results. The clean-up quotes varied from $700 to $14,000.
''It's not governed and there is not enough legislation. There are too many cowboys popping up saying 'we are qualified drug testers'.''
Tauranga Rentals owner Dan Lusby said he finished a one-day $500 training course with the only company he knew of that ''is doing any training for people''.
The industry is ''not that regimented''.
Mr Lusby said there was a market for opportunists and he was aware of operators paying $10 for a testing kit and then charging at least $200 to test a property.
''They are taking total advantage of people's fear.''
Mr Lusby, in comparison, said he billed his clients $50 per test and there had only been two positive results from a few hundred houses.
One of the contaminated houses was just above the recommended levels and the clean-up company had taken everything off the walls, he said.
''Another company said all they would have done was chemically cleaned it. Some will actually literally strip the house bare and that is where you get the big variation.''
''They are going way overboard taking it to the extreme and at this stage the general public and insurance companies don't know any different.''
Meth Solutions has been operating for more than five years and director Miles Stratford said the company had developed extensive systems, processes, policies, procedures, knowledge and experience.
But there had been an explosion of testing and decontamination companies across the country in the past 12 months, he said.
''When we started there was one commercial testing lab and half a dozen companies using their services. Now there are two commercial testing labs with around 35 companies each making use of their service.''
He also questioned the use of kits and the limited experience of many people administering them.
The industry standard the Government was looking at had potential to improve quality and outcomes -- although it would increase costs too, he said.
Graham Yorke, director of established testing company Meth Detection, estimated there could be dozens of operators with little or no knowledge or experience.
''All of my company field testers are licensed investigators under the Department of Justice ... and have been trained in forensic testing by a highly qualified training organisation,'' he said.
''In my view there should be standard practice involvement and minimum training levels set.''
His company had found Bay of Plenty homes with moderate to high contamination levels had dropped. One in seven houses were detected a year ago compared to one in 12 now.
Consumer NZ chief executive Sue Chetwin said the organisation had heard complaints ''about what is happening in this space and support the development of a standard''.
''It does appear to be a cowboy industry. The testers are the same people who do the clean-up so it's in their interests to find meth.''
''Not saying that they are all like that but a cowboy industry has developed around people's fears.''
Insurance Council chief executive Tim Grafton said there were conflicting messages about meth contamination.
''Insurers are facing increasing numbers of claims from property owners who are faced with levels of contamination from tenants passively smoking P right through to contamination from meth labs on the property.''
The new standard would mainly cover sampling, testing and fixing contaminated properties, he said.
''And the requirement for all parties involved in the process to be trained or qualified to a high standard.''
Building and Construction Minister Nick Smith said the lack of a New Zealand Standard for meth testing and decontamination had led to differing views on how bad properties were contaminated and how to fix them.
The new standard would address this, he said.
The new standard aims to provide guidance on methods, procedures and other supporting material that will ensure a consistent approach to managing the testing and decontamination of properties and contents. A committee of experts the Standards Approval Board approved had developed the standard.