Green Party leader James Shaw says media reports the Kermadec Ocean Sanctuary is to be scrapped are inaccurate.
Speaking on Q + A on Sunday, Mr Shaw said the the 620,000 sq km sanctuary, about 1000km northeast of New Zealand, was "still an issue to be worked through".
It had been reported by some media that the sanctuary, announced by Prime Minister John Key in 2015, was dead in the water because Labour's coalition partner New Zealand First doesn't want it.
"I don't think the sanctuary is in jeopardy," Mr Shaw said.
"We [the Greens] are committed to make it work, but it's a complicated issue."
Fishing companies and iwi bodies have filed legal action, opposing the sanctuary, saying it denies fishing rights agreed in Treaty settlements.
NZ First has well-known close ties to the fishing industry - tuna is prevalent in the waters near the Kermadecs.
Mr Key told the United Nations in 2015 that the Kermadec Ocean Sanctuary would be one of the world's most significant fully-protected areas, preserving habitats for seabirds and many species of fish and marine life.
Meanwhile, Mr Shaw said that while talks were already under way with respect to a Greens co-leader, it was not likely something that would be announced until the new year, after the summer recess.