Landlords have developed their own set of rules, barring them from renting dirty places, telling lies or making racist remarks to tenants.
The national landlord membership and lobby group, the Property Investors Federation, has released a guide which it wants members to show to tenants.
Federation vice-president Andrew King said most members were already following the code.
"There's nothing to stop members breaking it. We don't have any powers over them - that's the job of the Tenancy Tribunal and the courts. If we are aware of them not getting things right, then by keeping them as members we have a better chance of stopping them from getting into trouble.
"The code isn't to regulate them, it's to inspire professional and profitable behaviour and keep out of trouble."
Helen Gatonyi, manager of the TenantsProtection Association in Christchurch, praised the code and said all landlords should adopt it.
"Anything that helps the relationship between landlord and tenant or educates both parties has to be a good thing."
The rules demand that landlords treat tenants with respect, in a businesslike manner.
"A rental property should be treated as the tenant's home and regard will be given for the tenant's peace, comfort and privacy," the code says.
"Members should be aware of what government assistance may be available to their tenants in relation to their tenancy, and assist them if requested. Dishonesty, deception or misrepresentation shall not be used in any activities involving members' property business activities.
"When asked to supply a reference for a tenant, members will supply true and accurate information in order to assist the tenant and fellow rental property providers.
"Members will provide the premises in a high state of cleanliness at the start of each tenancy and act promptly to investigate and remedy any reasonable request by a tenant, maintaining the premises in a comfortably liveable standard consistent with the age and character of the premises.
"Members will monitor the rental market and take a responsible approach to setting rental prices by considering market rent levels and any other specific or uniqueconditions of the property.
The code also bans any discrimination.
"In advertising and tenant selection, members will choose the most appropriate applicant and will not discriminate against anyone on the basis of gender, marital status, religious belief, ethnicity, disability -physical or psychiatric- illness, age, political opinion, employment status, family status, or sexual orientation."
A tenant's right to privacy is demanded.
"Credit histories will not be obtained without the prospective tenant's written authority," the new rules say.
The code demands community responsibility. "Members shall have regard to the neighbours of their rental properties and will take all reasonable steps available to them to protect neighbours' peace, comfort and privacy from the member's tenants."