Is my agreement valid if one co-owner has not signed?
Question from Tony updated on 18th November 2010:
Our expert Jeff Montgomery responded:

The Residential Tenancies Act 1986 (the Act) applies only to the relationship between a tenant and landlord. A tenancy agreement can still be valid where there are joint owners, and a tenancy has been entered into with one of the owners. If the co-owner was never a party to your tenancy agreement (not recorded on the tenancy agreement, or never agreed to as being a landlord), then your obligations under the Act will be to your landlord that you entered into the agreement with.
Your landlord may need to seek independent legal advice regarding any disagreement they have with the co-owner, whilst ensuring they comply with their responsibilities as a landlord under the Act. If there is any uncertainty as to whether the tenancy agreement is valid or not, either party can make an application to the Tenancy Tribunal to have the matter resolved. To discuss your situation further, or for information about applying to the Tenancy Tribunal, you can visit the Department of Building and Housing website (www.dbh.govt.nz), or call 0800 TENANCY (0800 836 262).
The Department of Building and Housing provides information and guidance on building law and compliance, services including weathertight homes, and advice for tenants and landlords.