Houses used as P-labs could rival leaky homes as a problem, with a warrant of fitness system needed to reassure buyers, the Real Estate Institute says.
Chief executive Helen O'Sullivan has told The Dominion Post the meth labs that were being discovered were only "the tip of the iceberg".
"With leaky homes you have a profile of the kind of house that can be affected, but meth labs can be anywhere.
"Not surprisingly, meth cooks don't sign a register when they start up."
She called for a "warrant of fitness" system for houses, which would include a test for meth at a cost of $100 to $500.
But the Housing Minister Nick Smith says the scale of the problem dnot justify imposing an expensive test for meth contamination on property owners.