Tainui and Ngai Tahu, first to settle with Crown in 90s, entitled to relativity payments.
Waikato-Tainui and Ngai Tahu have received Crown Treaty payments totalling $138 million but are entering into an arbitration process because the tribes believe the payments are at the lower limit of their entitlement.
Cash landed in iwi bank accounts in December. For the North Island tribe the figure was $70 million, for Ngai Tahu $68 million. The sums are linked to their historic settlements - the two were the first to settle in the 1990s.
Each received $170 million but the Crown agreed to relativity payments - a mechanism to protect the value of their settlements vis-a-vis others - once all settlements passed $1 billion. That mark was hit last year.
Waikato-Tainui chairman Tom Roa told the Herald the Crown had calculated its obligation independently of the iwi.
"What we said was: 'Thank you very much. That's a major transaction, we need to go back to the iwi and ask them, well, do they accept that'. But actually by our reckoning the amount needs to be disputed."
The tribe's parliament, Te Kauhanganui, met in December to back a plan to enter into an arbitration process, run by a third party, which the Crown had agreed to.
"The Crown is saying that it owes us $70 million, and we're saying 'yes, you do owe us, but there are other areas that you haven't taken account of [in the payment]'."
Mr Roa said while its commercial arm, Tainui Group Holdings, managed its original settlement, the relativity cash could be targeted more directly at tribal institutions.
"A lot of [internal tribal] feedback is about developing the iwi, hapu and marae. So instead of having a central body that we have now, how do we develop entrepreneurship around marae? How do we develop housing among marae? How do we do that kind of development?"
Finance Minister Bill English said all parties had agreed to fast-track the process. He could not say when arbitration would begin but said the Crown had a contractual obligation to meet the payments.
"Agreements were made back in the mid-90s that were critical to getting the process under way. These iwi took a very brave step at the time to be the first to settle. Is it an ideal mechanism? No, of course it's not. But it does deliver basic fairness."
The Iwi Chairs Forum questioned Prime Minister John Key on the settlement issue during its open meeting yesterday with ministers.
In Northland the pace of settlements is uneven. Ngapuhi, the country's largest iwi, is in line for the last big payout.
Mr English said as well as three Te Hiku iwi who yesterday signed a social accord with the Government, the total value of settlements would be worth hundreds of millions of dollars to the region.
The Prime Minister said the Te Hiku grouping of potentially five iwi was worth $200 million alone.
The roadblocks to settlement include internal mandating divisions within Ngapuhi, and Ngati Kahu potentially not choosing to rejoin the Te Hiku forum or engage with the Government after losing a recent Waitangi Tribunal hearing on its settlement.
Mr Key said the need to settle in the region was pressing.
"It would do what it's done around the rest of the country, it would give those iwi some financial independence and some real capacity to make a difference to the lives ... of their members ... and I think no place is that more important and necessary than here in the Far North where there is real deprivation."By Yvonne Tahana Email Yvonne