New Zealand is at odds with its neighbours over major sticking points in the draft climate change agreement being negotiated in Paris.
Ministers from 196 countries start the high-level segment of the United Nations climate change conference tonight.
A text has been agreed to but there are still plenty of serious hurdles left for the week ahead.
Climate Change Minister Tim Groser said how legally binding the agreement would be would take up some time over the coming week.
Mr Groser maintained New Zealand's proposal to have an overarching binding agreement, but not make the emissions reductions targets mandatory, was the right way to go.
"You do not need to be a rocket scientist to know that a legally binding commitment means that we say bye-bye to the United States and we're wasting our time.
"People take time to adjust to that reality and that is still unresolved, but I honestly cannot see an agreement coming out without some flexibility on this," Mr Groser said.
New Zealand's position is supported by the US, but not Britain, China, the European Union or Pacific Island nations.
The draft text also contains two options for the global temperature rise limit.
In the lead up to the talks, the focus had been on getting a deal that would limit the warming of the planet to 2°C above pre-industrial levels.
But tough negotiating by small island states, and members of the G77, has seen both 1.5°C and 2°C left as options in the text. Australia is reportedly also in support of the 1.5°C limit.
Tuvalu Prime Minister Enele Sopoaga said the limit must be 1.5°C as the future of his country, and many other Pacific Island nations, was at stake.
However, he would not say whether Tuvalu would block the deal over the temperature limit.
Mr Groser acknowledged it was a sensitive matter for Pacific Island nations, but did not want the talks to be bogged down over the issue.
"Having said that we will work with our Pacific friends to keep this alive, we do understand what drives this from their perspective," he said.
"I just don't want to see the conference fall over on something, which at the end of the day is just an aspirational goal."
There will also be debate at the talks about when to review emissions reductions targets, but also whether countries should have to increase their targets after a set amount of time.
An official non-government observer at the talks, Barry Coates, said because the current pledges to reduce emissions were not good enough, the idea of a ratcheting up mechanism was critical.
"We have pledges from governments that don't add up to enough, and particularly New Zealand's pledge is not good enough, but this ratchet mechanism depends not only on what countries are willing to pledge in terms of cuts to emissions, but also what they are prepared to contribute in terms of finance," he said.
"Finance is going to be probably the crucial element in the end game, as it was always going to be."
The sticking points around finance have remained the same in the lead-up to the talks, and for the past week: who should pay, how much, to whom and how will it be distributed?
The high-level segment of the conference will officially open at 10pm (NZT).