Auckland councillor Chris Darby has asked council officers to investigate the practice of converting garages into so-called "utility rooms" where families desperate for accommodation are sleeping.

A Herald expose found dozens of property listings featured conversions termed "utility rooms", which were not consented and could not be advertised as bedrooms under the Building Act.

The Act says bedrooms must meet guidelines for habitable spaces, and says sleeping areas must be insulated and damp proof; and have adequate light and ventilation, among other factors.

Despite that, a number of real estate agents approached by the Herald advocated renting the