The owners of an Auckland property are being sued by their tenants who say they knew it was contaminated with P when they let it out.

The family of three only learned about the P problem when the house went up for sale, and a prospective buyer asked for a meth report.

Graham McCready is claiming $50,000 compensation for the tenants.

He said they suffered health problems, which especially affected a boy who was in the most badly affected bedroom.

"He was off [school] 35 days in one term which is severe and they all had strange medical conditions," said Mr McCready.

He's filed a claim with the Tenancy Tribunal saying the landlords failed to comply with Health and Safety Regulations.

He's seeking a refund of rent and cost of moving out.

The family claims the landlord knew from the outset that the property was uninhabitable.