The Government is pushing ahead with new rules to get heating into nearly 500,000 rental homes - a move which landlords fear will force them to install heat pumps and critics say will push up rents.

Housing Minister Phil Twyford told the Weekend Herald the Ministry of Business, Innovation and Employment would soon call for feedback on compulsory heating in rental properties.

"Subject to ministerial and Cabinet decisions, the ministry expects to consult on the regulations that will set the proposed standards and the timeframes for landlords' compliance later this year," Twyford said.

But the fixed form of heating would not necessarily be heat pumps and his experts were yet to consult on the finer details and make recommendations.

The cost of heat pumps varies considerably but averages about $2000 for the unit and a further $1000 for installation, according to Consumer NZ. Heat pumps are regarded as the best form of heating for most larger homes, as they cost far less to run than normal heaters for the same level of warmth.

Twyford said the Healthy Homes Guarantee Act, which was passed last December and comes into effect on July 1 next year, would create standards landlords must comply with.

"One of them relates to heating in tenanted premises. The consultation to develop regulations will explore making a fixed form of heating compulsory in rental properties. The other standards relate to insulation, ventilation, moisture control, draught-stopping, and drainage."

However, NZ Property Investors Federation executive officer Andrew King said he expected the new MBIE regulations would demand heat pumps because Labour had campaigned on that. The federation has already expressed concern about the scheme.

"We don't want to be dictated to or prescribed to. Installing fixed forms of heating will cost money and put prices up. A lot of properties like apartments don't suit heat pumps and the body corporate might not allow it, meaning an apartment couldn't be rented out," King said.

A spokeswoman for Twyford stressed that the fixed form of heating was yet to be defined but was likely to be the best form of heating for the house. "Heating devices would need to meet certain criteria."

A consultation document was planned to be released for public feedback, the spokesperson said.

The federation has complained that some tenants will not use heating systems provided and make places harder to heat by not opening curtains during the day to let sunlight in, drying clothes inside and using unflued portable gas heaters.

Judith Collins, National's Housing spokesperson, asked if Housing New Zealand had the budget to install fixed heating devices in all 63,000 properties it owns or manages.

"This will mean mass installation of heating which will mean an increase in rent. I'm a big fan of heat pumps and I note that they are also excellent at limiting condensation and mould but it is important to remember that these costs will be passed on. I presume that the Government will need to increase the accommodation supplement payment," she said referring to lower-income tenants on state support.

"As New Zealand's biggest landlord, Housing NZ will need to set an example and install devices in all their homes that don't already have them. I trust Phil has checked he has the money, sufficient devices in New Zealand, enough tradespeople to install them and he is better prepared than he has been for KiwiBuild," Collins said.

Twyford said Housing NZ had already budgeted for the changes and would spend about $90 million installing heating and bringing state houses up to standard.

Bruce Gordon, chief executive of ventilation business HRV, said some tenants would enjoy the benefits of the new act before next year because landlords were already improving properties.

"People have been demanding warm dry homes for years and something has finally happened. When a house has mould, it has it year-round and it is unhealthy," he said.

MBIE already stresses the need for heating: "Landlords should make sure their rental properties can be well heated and ventilated. Warm and healthy rental properties help tenants avoid illnesses and make them more likely to stay longer."

Census 2013 said New Zealand had 453,132 rental dwellings "not owned and not held in a family trust, rent payments made". Auckland had 154,347 rented dwellings.