Prime Minister Christopher Luxon says remaining in the Paris climate agreement is a bottom line in any coalition negotiations after the election.

New Zealand has pledged to halve its emissions by 2030.

Treasury estimates that could cost the country up to $5 billion in overseas carbon credits but the government insists it will not send billions of dollars offshore to meet the target.

National’s current coalition partners have indicated they do not support the commitment as it stands.

ACT says New Zealand should leave the Paris Agreement unless it set new “realistic” targets, and New Zealand First has also raised doubts about it.

Luxon said he did not support their attitudes, and remaining in it would be a non-negotiable in coalition negotiations.

“It’s in New Zealand’s interest to be in the Paris Agreement, because as soon as we would come out, we’re in bad company, there’s only four countries that have pulled out,” he said.

Doing so would make the country poorer, because New Zealand products would be “kicked off the shelves” overseas, Luxon said.

“Are there problems with Paris? Absolutely … we’ve got a big target to try and hit by 2030, we’ll do everything we can.

“But equally, I’m not going to go send billions of dollars offshore, I’m going to do everything we can to try and hit that target.”

Luxon said there would need to be “a reckoning” at some point because around three quarters of the countries signed up to the Paris Agreement are off track.

Luxon is heading to the tiny Micronesian islands of Palau this week for the Pacific Islands Forum leaders’ meeting with heads of government.

The Forum said climate change was the single greatest threat to the Pacific.