It's unclear how much the Labour government will raise, from its just announced new capital gains tax.

The targeted tax would apply to profit made from selling commercial or residential property, to raise funds for universal free doctors visitors.

The family home, farms, KiwiSaver, shares, business assets, inheritances, and personal items will be exempt.

Infometrics Principal Economist Brad Olsen told Ryan Bridge the announcement doesn't specify how much the tax is likely to raise.

He says it's hard to assess based on the information whether the tax would raise millions, hundreds of millions, or billions of dollars of revenue over any time period.

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