The Auckland floods and Cyclone Gabrielle caused between $9 billion and $14.5 billion of asset damage, according to Treasury estimates.
According to official forecasts, residential property damage will range between $2 billion and $3.5 billion, business property damage will range between $2 billion and $3 billion, and public infrastructure damage will range between $5 billion and $7.5 billion.
The estimates include the costs of both insured and uninsured damage, and Prime Minister Chris Hipkins ruled out a cyclone levy to help pay for uninsured damage.
According to the Treasury, damage to transportation infrastructure such as roads and bridges, as well as water infrastructure, would account for a large portion of the government's repair bill.
The Treasury noted that, in addition to the cost of repairing physical infrastructure, the cyclone and flood would result in lost economic output.
It stated that primary industries would bear the brunt of the costs, some of which would still be ongoing.
It estimated that crop and other agricultural production losses would cost $400 million to $600 million in the first half of this year, with "persistent losses" of about $100 million per year as a result of longer-term damage to orchards.
