An Auckland property investor and developer has told victims of properties where meth has been smoked to clean their houses with sugar soap or other common cleaners.

David Whitburn, an ex-lawyer and author who was also Auckland Property Investors Association president, said the alarm over meth cleanup in lightly contaminated places was unnecessary.

But Simon Fleming, a director of testing business Meth Xpert NZ, said he was concerned about the advice because professionals should be brought in to clean up contaminated houses. Cleaning products might reduce meth levels but would not bring them down to levels which he considered would be safe.

Whitburn disagreed.

"You don't necessarily need to call in expensive meth-remediation companies who charge thousands of dollars to fix a property where meth has been smoked. It's different if the place has been used as a clandestine lab because contamination will be much more serious.

"But if meth has just been smoked there, the levels will be lower and that means you can use products like sugar soap, bleach and other household cleaning agents bought at supermarkets for just a few dollars," he said.

Fleming stressed that his business tested but did not clean up places. But he doubted Whitburn's advice.

"Sugar soap is one of the first steps in the process. Meth is water-soluble so it will break it down somewhat but there will still be levels of contamination.

"A professional cleanup is the right way to go," he said, citing the need for specific cleaners and people wearing protective clothing.

Whitburn said some landlords had already taken matters into their own hands, before the new Sir Peter Gluckman report was issued last month, debunking the meth house myth.

"I know of two Auckland Property Investor Association member whose places were contaminated. They bought their own testing kits for just over $100, worked out the level of likely contamination. They decided to take matters into their own hands. They used sugar soap on the walls, window ledges, floors, cupboards and ceilings.

"They then had their places re-tested by independent companies and the levels were below the 0.5 microgram standard now in force by Standards NZ," Whitburn said.

He strongly advised people with meth-hit houses to consider replacing all curtains, blinds and light fittings: "Those fittings can be cleaned but in some cases it's just easier to replace them."

With carpets, Whitburn said people could hire supermarket carpet cleaning devices because these wash the carpet and its backing.

"That has been shown to significantly reduce contamination levels by APIA members.

"Carpets come out not as badly contaminated afterwards."