Leader James Shaw released the party's rental policy today in Wellington, which aims to lift minimum standards, make renting more secure, and give tenants more power in relation to landlords.
"Over half of the population is now renting and they deserve the same standards as people who own a home," Mr Shaw said.
The policy included a $500 million boost to the Warm Up NZ scheme, a National-Green initiative which offers homeowners grants of up to $2500 to get their homes insulated.
The Greens have long wanted a warrant of fitness (WOF) for rental housing, but today they said it would be compulsory by 2019 if they were in power.
That meant rentals would have to meet a basic standard of heating, insulation and ventilation, and landlords would have to the property re-checked every three years at a cost of around $150-$250 (on top of the cost any repairs).
There would be a further $50 charge for landlords to be part of a mandatory registration scheme, similar to the regime for taxi drivers.
While the exact rules would be set after consultation, the Greens suggested that the requirements could include a demerit point system.
Like tenants, landlords would have to pay a bond at the beginning of a tenancy which could be used to pay any maintenance costs if rental properties fell below a minimum standard.
Shaw said renters should have more security, and his party wanted fixed-term leases to have a default length of three years, unless the landlords and tenants agreed to other terms.
Tenants would have an automatic right of renewal at the end of the three years, and they could not be evicted without cause.
Any formula for raising rents will be included in the initial contract and will he limited to once a year under the Green policy.
A new tenancies advocacy service would also be created to advise tenants and landlords.
The National-led Government has ruled out a warrant of fitness, but recently made it compulsory for rentals to have insulation and smoke alarms by 2019 at the latest.
National leader Bill English said today that the Government had to be careful to set standards which did not make it harder for people to get into housing or push up rents.
He said most rental properties in New Zealand were warm and dry, though some were "not at a level we would like to see".
Labour wants a broader set of minimum standards, similar to the Greens policy.
A Labour bill currently before Parliament which would set higher insulation standards and also introduce heating and ventilation standards.