The Tax Working Group report, published last week, recommended a comprehensive capital gains tax on investment property, shares, farming and others businesses at the tax-payer's highest income tax rate.
Exemptions would apply to the family home and personal goods such as art and jewellery and vintage cars.
Tax would be applied after sale on the gain in value between April 2021 and the sale price.
Ardern said she was not going to give a definitive view on the recommendations while she was trying to get consensus among three parties, Labour, New Zealand First and the Greens.
But she used most of her post cabinet press conference in defensive mode, laying the groundwork for what looks likely to be a diluted capital gains tax.
New Zealand First appears unlikely to support a capital gains tax applying to farms and other businesses but may support one on property investments.
Ardern said she knew some of the discussions that would be happening in rural New Zealand and among small business owners about the tax.
"I grew up in Morrinsville. I grew up in a rural community. I certainly hear and know some of the discussion that is being had in that quarter," she said.
"All of my first jobs were predominantly with small business owners and I was a small business spokesperson in Opposition so I hear that too.
"I have in my mind a range of experiences, a range of views that I will - as will all of us in Government - be weighing up when we determine which option that we adopt and where we form consensus."
She said the recommendations of the Tax Working Group amounted to 0.4 per cent of the Government's annual tax income in Year One and four per cent in Year 10 - and anything gained through a capital gains tax would be returned through a tax switch, Ardern said.
It was far from National's claim that it was "an attack on the Kiwi way of life."
The Tax Working Group estimated that a comprehensive tax – without the likely dilution - would raise $8 billion over five years.
"We have, by and large, a tax system that is fair, one which works well, but we have also been presented with a series of recommendations to close the remaining holes in the system."
Ardern also weighed into the debate over whether CGT should be seen as a generational issue - some have framed it as a tax on the wealth accumulated by baby boomers which could reduce property investments and make housing more affordable.
"I don't think we gain anything by apportioning blame here," said Ardern.
"Past generations have operated under the system that was operating at the time. They've made investment decisions based on that."
That was why it was fair the proposed CGT not be retrospective, because people had acted in good faith in their investment decisions.
"But we do have to be mindful of the next generation's opportunities. That means as much for us about initiatives like affordable building and buying as it does [about] some of the other debates we are having."
