A homeowners' advocate is extremely concerned about the Government's about-turn on meth contamination.

Chief science advisor Sir Peter Gluckman says there's no scientific evidence third-hand exposure to meth smoke residue poses a health risk.

Housing New Zealand has swiftly responded by reducing its maximum levels for residue.

Home Owners and Buyers Association president John Gray told Leighton Smith that's a risky approach.

"That gives me cause for concern for the health and wellbeing for those vulnerable people in our community who might be put back into these Housing New Zealand homes."

LISTEN TO JOHN GRAY TALK WITH LEIGHTON SMITH ABOVE