The government will find itself in serious trouble if it starts disregarding iwi mandates when it comes to Māori land, the co-chair of the Labour Māori caucus, Willie Jackson, says.
But land rights, or a lack of in the case of Ihumātao, is precisely what has drawn hundreds of peaceful protesters to Auckland.
Mr Jackson said he sympathised with those on the frontline, but the government had to respect the settlement.
However, the Green Party disagreed, and co-leader Marama Davidson said the way the Crown recognised mandates was flawed and that was what caused the whole mess.
Ihumātao is located next to the Stonefields Historic Reserve in Māngere and is considered wāhi tapu, or sacred, by local hapū and iwi.
In 2014, 32ha of the land was designated as a Special Housing Area prompting a group of protesters known as SOUL (Save Our Unique Landscape) to begin its peaceful occupation.
Fletcher Building now owns the land and in an unusual move struck a compromise with Te Kawerau Iwi Tribal Authority to return 8ha to mana whenua - the iwi with historic and territorial rights over the land.
The prime minister and Labour Māori caucus say the dispute was for mana whenua to sort out, but Ms Davidson said that didn't go far enough.
"Te Kawerau have got a good mandate but there are a whole load of other iwi ... who are on the frontline who don't agree to what is happening and they have just as much say over their land,'' she said.
Jacinda Ardern is still reluctant to weigh in.
"This has been an issue for between the developer and mana whenua and, of course, some of those issues have been tested in the Environment Court and the Waitangi Tribunal, and that's why I say ultimately everyone wants to see resolution here but I do think that needs to be found from within the mana whenua,'' she said.
Mr Jackson said he understood that some felt ripped off, but warned that siding with anyone other than those with the mandate was a dangerous path.
"The day we walk away from mana whenua is the day we might find ourselves in real trouble. Right now we're committed to supporting to what they've signed up for - as hard as that might be,'' he said.
Ms Davidson and her colleagues are heading to Ihumātao today to show their support for the protest, and she blames the Treaty of Waitangi settlement system for the tensions.
"What happens when you ignore all the other iwi interests involved is this mess. And the Greens have had a longstanding position of also listening to those disaffected groups as well,'' she said.
Mr Jackson said there were people on the frontline who felt a strong sense of injustice but when those who have rights over land make a decision - like the deal done with Fletcher - the government had to support that.
"We understand the hurt but sometimes people, particularly our mana whenua, have got the right to make these decisions and we're not going to say you're wrong and get out of there. I know others are doing that but we wouldn't be so bold or so arrogant,'' he said.
The Green Party campaigned in 2017 on reviewing the entire settlement process,and there are MPs within the Labour Māori caucus who also acknowledge its flaws.
But having already signed their settlement, the government believes Te Kawerau's battle is no longer with the Crown, instead it lays with those committed to holding the line for as long as it takes.