Judith Collins posed the possibility today that Green Party co-leader Marama Davidson could potentially be Deputy Prime Minister under Jacinda Ardern - a scenario the National leader said would be "challenging for the country".
Collins said she has "nothing" against Davidson, but she hopes "she stays as co-leader of the Greens".
"[Davidson] says that tax is love - that says it all, really."
Earlier in a speech, Collins said Green MPs thought tax was love "because before they came to politics they never paid much tax, did they?"
When asked what that meant, Collins made a jab at the party, saying "most of them are unemployable, I would have thought".
"A whole lot of them - I don't think I should be nasty but it's the truth."
Green Party co-leader James Shaw said National was "clearly getting more desperate by the minute".
"They can’t land their attacks with Labour so are scrambling to attack us in the final 72 hours by spreading misinformation.
"Judith Collins might not share this view – but we unashamedly believe that paying tax is a positive contribution that we all make to live in a civilised society.
"Chipping in to ensure strong public services is particularly critical after the National Party ground them down into disrepair for nine long years."
Shaw said he was proud of Green Party caucus and candidates "made up of former small business owners, human rights lawyers, international climate negotiators, councillors, consultants, psychotherapists, advocates and student strikers".
Earlier, Collins claimed if Shaw were to be Deputy Prime Minister, he could make changes as acting-PM and bring in the wealth tax.
Ardern called the statement "not only desperate" but "also ridiculous". She said National, if it were elected to govern, would most likely partner with ACT "who want to freeze any minimum wage changes for three years and who want a flat tax".
"We, however, are not accusing National of adopting those policies."
When told of being called "desperate" by Ardern, Collins said, "Did she really? Oh she shouldn't go into name calling."
Shaw said Collins was being speculative.
"The Deputy Prime Ministership is just a number of ministerial roles that need to be looked at. We will do that towards the end of the negotiations once we know what the work programme is that we've agreed with the Labour Party."