The Government needs to reveal how many of more than 550 state houses might have been left wrongly vacant because of Housing New Zealand's methamphetamine contamination testing, the Opposition says.
The agency has faced immense criticism after it was revealed incorrect standards were being used, potentially resulting in hundreds of unnecessary evictions.
According to the Ministry of Health, the test for lab contamination - which is much more serious - should not be used to determine the safety of houses where the drug had been smoked.
Housing New Zealand has denied MoH claims they were repeatedly told the standard was being misused.
Labour housing minister Phil Twyford says 558 state houses are potentially caught up in the "dodgy testing procedures".
He accused Social Housing Minister Paula Bennett of being "strangely quiet" on the incident, and urged her to explain how many homes had been needlessly vacated.
"If those 558 houses are not contaminated, and do not pose a health risk to the tenants then there are hundreds of Kiwi families desperate for an affordable rental home that sure could use them," he said.
Former government minister and Maori Party founder Dame Tariana Turia says she knows of a case where children were taken away from a family on the basis of a meth test in their home.
"From what we could gather the house had not been tested before the family move into it," she said.
"They not only punished the family, they also reported them to Child Youth and Family and their two children were removed from their care."
Dame Tariana says that happened despite the family vigorously denying anyone had made or smoked meth in the house.
HNZ's testing has also resulted in a proliferation of testing companies, which have been charging high fees - money HNZ is reportedly trying to claim back from tenants.