"Our analysis detailed that debt serviceability restrictions, such as a debt-to-income (DTI) limit are likely to be the most effective additional tool that could be deployed by the Reserve Bank to support financial stability and house price sustainability," it said in a statement.
"The analysis also demonstrated that any such restrictions would impact investors most powerfully while having limited impact on first-home buyers."
House prices in New Zealand have escalated because of returning economic growth post-Covid, record low-interest rates and expansionary economic policy.
Sam Stubbs, co-founder of Simplicity, said today: "Someone has to keep the banks honest, and the current interest rate climate supports lower mortgage rates.
"The main banks currently charge from 3.4 per cent to 4.59 per cent for a floating rate mortgage. At those rates the banks aren't being robbed, they're doing the robbing," Stubbs said today.
Floating rates that are that expensive force borrowers into fixed-term borrowing, with penalty and break fees, he said.
"And the banks offer cheaper fixed rates because they want borrowers to renegotiate your
mortgage every year or two. That allows them to sell more high-fee products like credit cards and insurance," Stubbs said.
Simplicity first-home loans are for 30 years and have a floating interest rate. That means any or all of the principal can be paid off at any time, without penalties or break fees.
It also offers online pre-approvals and mortgage applications.
In January, Westpac dropped its one-year fixed-term mortgage rate to 2.29 per cent.
The Herald reported then that SBC is also lower than the majors with a rate of 2.25 per cent.
But there are conditions attached to get the low rates.
Those wanting the ANZ rate must have 20 per cent minimum equity and an ANZ transaction account which their salary is direct-credited into.
The special is also not available with package discount offers.
Westpac's rate is only available to customers with 20 per cent equity in owner-occupied homes.
While low-interest rates can be appealing, homeowners are advised to first check with their bank or mortgage broker to find out if the associated break fees make the savings worthwhile.
The low rates currently come at a time of growing concern about the state of the property market in New Zealand.