ANZ Bank home loan customers will have access to interest-free advances to help insulate their houses from next month.

ANZ New Zealand announced the $100 million initiative today at the Expol insulation plant at Onehunga with Prime Minister Jacinda Ardern.

David Hisco, chief executive of ANZ, said insufficiently installed insulation is a major problem in New Zealand and the bank wanted to help resolve the issue.

"Cold, damp and mouldy homes are a major problem in New Zealand, resulting in many health problems, expensive energy bills and degradation of properties," Hisco said.

"ANZ wants to help New Zealand resolve this major social, environmental and economic problem. Properly installed insulation can transform an unhealthy home literally overnight and vastly improve the quality of life – particularly for children."

The loans will be repayable over a maximum of four years and be for a maximum of $5000 per house for up to two houses.

They will be available to home owners and landlords who use registered builders and certified insulation installers.

A $5000 interest-free home insulation loan would cost a home owner about $100 a month to pay off over 48 months.

Successive governments have introduced efforts to encourage or compel property owners to install insulation.

The previous National Government introduced rules that rentals needed to have certain insulation by mid-2019.

These requirements were beefed up by the current Government with the Healthy Homes law, which made changes to ensure that all rentals meet minimum heating and insulation standards.

The Government also offers $2000 insulation grants to help make Kiwi homes warmer and drier.

The "ballpark" estimate for insulating an average Kiwi home (100 square metres) could cost between $3500 and $5900, according to Expol's website and insulation calculator builderscrack.co.nz.

According to Smart Energy Solutions, up to 35 per cent of heat is lost through the ceiling and 10 per cent through the floor in the winter.

This isn't the first time New Zealand banks have lent a hand to insulate homes.

In 2009, all major banks agreed to participate in a home-insulation programme slated by then-Prime Minister John Key.

The scheme provided government grants of up to $1300 towards a third of the cost of insulation and a $500 grant for clean heaters, with loans being available for the remaining cost.

The government's May 2009 budget allowed for $323m over four years to retrofit 180,000 homes with insulation and clean-heating devices.