Tenants could be exploited under proposed laws requiring rentals to be insulated and have smoke alarms, Catholic advocacy and aid agency Caritas Aotearoa says.
Under the Residential Tenancies Amendment Bill, ceiling and underfloor insulation will need to be retrofitted in social housing by July, and in all other rental homes by July 2019. It could cost landlords up to $3000 per property to comply.
Caritas Aotearoa manager Lisa Beech told Parliament's Social Services Select Committee there would be nothing to stop landlords from passing that cost on to tenants.
In some of those rentals the upgrades were necessary, rather than being nice-to-haves, she said.
"We wouldn't allow people to sell rotten fruit in supermarkets and then charge the consumer for checking that they actually get what they paid for.
"I think there's an element in housing in which we're leaving tenants to complain about the quality of housing they're receiving."
Ms Beech said rentals needed to be both good quality and affordable.