Christopher Luxon won't outline what proposals from ACT's policy platform National could adopt in any post-election coalition negotiations - though he appears adamant National's tax plan will be introduced.
The latest Newshub-Reid Research poll showed National and ACT could form a Government if the results were replicated on October 14. The results showed National had 40.9 percent of Kiwis' support, while ACT was on 10.1 percent. That would give them 66 seats.
Luxon is now coming under pressure to explain to voters what a possible National-ACT Government could look like, including what elements of ACT's manifesto it could adopt.
But he's not budging, saying that's an issue for after the election.
He's previously ruled out getting rid of the Zero Carbon Act and explained what policies of ACT's are not National's. But he hasn't been explicit about which ones National couldn't stomach at all or what it could submit to if needed during any negotiations.
Asked on Wednesday if there was anything from ACT's tax plan that National could accept implementing, Luxon said he hadn't looked at it closely.
"I haven't looked at the detailed policy from ACT and I won't because at the moment I am the leader of the National Party and that's what I am focused on," Luxon said.
Does that mean he was leaving the option open?
"No, I like our tax plan. I really like our tax plan. The fact that we have it fully funded, that it's separate from the fiscal plan, the fact that we can actually deliver that moment to low and middle-income people."
He said National would be "doing our tax plan" as it is "a great one" and "the best answer".
National's tax plan involves adjusting income tax brackets for inflation, paid for by new revenue streams like a foreign buyers tax. ACT wants a two-rate income tax system, though has suggested the current economic conditions may mean changes to its plan.
While Luxon has said previously that he doesn't support ACT's treaty referendum policy, he didn't say that on Wednesday when asked if it was something he was prepared to rule out.
"I appreciate you want to get into it. I am not negotiating a coalition agreement with the media this side of an election."
He said it wasn't fair to suggest everything of ACT's is on the table, but wouldn't say what wasn't.
Luxon said he wouldn't get into post-election negotiations prior through the media and prior to the election
"What I am focused on right now as the leader of the National Party, is making my case to the New Zealand people is if you want a guaranteed change of government, if you want to change the direction of this country, I don't want you supporting any other party."
He said National "will work with our coalition partner if we need to on the other side of the election."
Seymour later agreed that the parties wouldn't negotiate through the media.
"We have a strong personal relationship, we have clear professional differences. We are going to work through those together if the people choose us to govern," Seymour said.
He said the economic circumstances would affect the next Government's fiscal policy "rather than the parties".
"I think we're going to have to work really hard together to navigate some pretty choppy waters."
Seymour earlier this month suggested ACT could only provide 'confidence' to National if the two parties can't fully share power. He has since said he doubts that will be needed as he expects National and ACT to be able to work together.
Luxon has also refused previously to rule out working with New Zealand First if it returns to Parliament after the election.