Prime Minister John Key is not ruling out working with New Zealand First in the future, saying he will spell out potential partners ahead of the next election.
National banned post-election deals with New Zealand First in 2008 and 2011 but Mr Key did not rule out working with the party after the 2014 election in an interview on The Nation this morning.
"I don't know the players in 2014," Mr Key said.
He said he had been the "most upfront" of any party leader on the issue of potential coalition partners.
"I've spelt out very clearly before every election... and I'll be doing the same in 2014," he said.
He said New Zealand First leader Winston Peters was "tricky" and there were a range of issues relating to him.
New Zealand First had 2.8 percent support in the latest TV3 poll, while most of National's current coalition partners are struggling.
Mr Peters has set maintaining the age of eligibility for superannuation at 65 as a bottom line for New Zealand First in any coalition negotiations after the 2014 election, the Weekend Herald reported today.
National's policy is also to keep the age at 65 even though commentators say the policy is unaffordable in the long-term and other parties are shifting policy on the issue.
"This is my challenge to Winston Peters. I dare him to go out there and say he will not under any conditions form a Government with Labour even if Labour's policy is to raise the super age from 2020, not in the three-year period from 2014 to 2017.
"I dare him to say that. He will not... because he's tricky," Mr Key said.
New Zealand First is holding its annual conference in Palmerston North this weekend.