Fears the Government's new construction requirements will unintentionally create a monopoly.
The Government's announced mandatory warranties for new homes three storeys or less, and all renos worth at least $100,000.
Building and Construction Minister Chris Penk says it's intended to protect homeowners from cowboys.
Combined Building Supplies Chief Executive Carl Taylor told Mike Hosking there's been difficulty in the past to get insurers on board.
He says there is work to change this, because there is much need for more competition in this space.
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Mark the Week: 'Horse-faced duck' gave a look behind the scenes at Labour
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Mike's Minute: My thoughts on the Budget
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Richard Arnold: US Correspondent on the latest draft plan for an extension to the ceasefire between Iran and the US
03:14