National Party leader Bill English is warning the incoming Government against any "experimental change" that could wrench the country off its solid economic base.
"Part of our job, as a uniquely strong, large opposition - bigger than Labour and NZ First put together - is to make sure that they run a Government that's positive for New Zealand, not one that is trying some kind of experimental change which would leave the country in worst shape than they got it," English told Radio NZ's Morning Report.
"They have created some very high expectations on the one hand, and I think a fairly confusing picture of the amount of change on the other."
English questioned New Zealand First leader Winston Peters' comments about an economic slowdown, "just when many New Zealanders have had real confidence in the economy and where it's going".
The National Party has 56 seats in Parliament, Labour has 46, NZF has 9, the Green Party has 8, and Act has 1.
English said that the election result was legitimate but unusual, and posed issues for the Labour Party.
"This is a Prime Minister who's the first one in 100 years who lost the popular vote, and lost it by quite a bit. And in making decisions about the future direction of this country, the Government will need to take into account those circumstances."
The issue of National's leadership is expected to be discussed at a caucus meeting today, but English declined to say whether he expected to continue as leader.
"That's a matter I'll first address with the caucus. I've been slightly overwhelmed by the amount of support in the days since that announcement [last Thursday].
"My measure of talking to a lot of them in recent days is they're more focused as a group on how to ensure that the huge gains made in this country can continue, and how to hold to account a Government that's been put together in an unusual way."
It is understood that the caucus will strongly endorse English to continue as leader.
English declined to comment on the possibility of senior MPs resigning, but added that
"Steven [Joyce] has indicated publicly that he'll be staying around, and that's great."
English told Newshub that National wanted "to see New Zealand continue to benefit from a strong economy. We also want to hold them to account on issues outside the economy".
"We'll get to see today whether they actually do have a plan for reducing poverty, whether there is a plan for lifting incomes."