The Bill that requires rental properties to be fitted with smoke alarms and insulation is close to becoming law.
It passed its committee stage in Parliament last night and has one more stage to go, its third reading.
Building and Housing Minister Nick Smith says it will cover 120,000 properties that don't have smoke alarms and 180,000 that aren't insulated.
When the Bill is in law, smoke alarms will have to be fitted by July 1 this year and insulation will have to be in by July 1, 2019.
The Residential Tenancies Amendment Bill also strengthens the enforcement of existing regulations around heating, dampness, electrical safety, plumbing, sanitation and ventilation.
Labour says it doesn't go far enough. It wants a warrant of fitness regime for rental properties.
Dr Smith says that would cost $100 million a year to administer.
"The Opposition argument that we should have no regard for costs is mistaken," Dr Smith said.