The signing of the "Treelords" deal, the country's largest Treaty settlement so far, could trigger top-up clauses in claims settled long ago.
Waikato-Tainui and Ngai Tahu signed landmark deals in the 1990s that included clauses for extra payments if the $1 billion mark was passed in overall settlements.
Tainui are seeking government clarification on the implications of the Treelords deal for their settlement.
Ngai Tahu kaumatua Tahu Potiki said last night the tribes could receive tens of millions of dollars each.
Leaders from seven Central North Island iwi and 600 of their members converged on Parliament yesterday for the signing of their $500 million deal that transfers ownership of the land on which Kaingaroa and other Central North Island forests stand.
The relativity clause in older agreements would pay 17 per cent of the value by which total settlements exceed $1 billion. The total amount committed to settlements by February this year stood at $817 million.
A spokesman for Treaty Negotiations Minister Michael Cullen said the relativity clauses were a few years from being triggered because not all of the components in the Treelords deal would be counted.
Less than half of the deal's worth _ about $200 million, which represented the forests' land value _ would be counted, he said.
Settlement amounts also had to be converted to 1994 dollars, which the Tainui legislation set out. That would put the $1 billion mark at least a couple of years away.
But Waikato-Tainui executive chairman Tuku Morgan said the latest deal could put into play the relativity clause.
"Clearly we don't have certainty as to whether the Government has exceeded the fiscal cap," he said.
"But we're confident that in the not-too-distant future we'll be sitting down with the Crown."
He wanted to meet the Government as soon as possible to "clarify" just what could be counted.
"One of the issues for us is that settlements have been struck, but they've since had value added to the primary settlement. What does that mean for the clause? We're not sure."
But for those Central North Island iwi _ Ngati Tuwharetoa, Tuhoe, Raukawa, Ngati Manawa, Ngati Whare, Ngati Whakaue and a confederation of Te Arawa _ who travelled to Wellington yesterday, the mood was about celebrating an achievement of pragmatism and innovation after years of intractability.
This was the fourth attempt over two decades to settle the contentious forestry question, which had caused real ill-feeling between and within iwi.
Tuwharetoa paramount chief Tumu te Heuheu, who is credited with leading the process on the Maori side, said the focus now had to be on development.
CNI iwi were now the largest forestry owners in the country and capitalising on increasing demand for wood products was the next step.
"The real chance for success lies immediately in front of us," said Dr te Heuheu.
After the deed signing, Dr Cullen said the settlement was unique in that it was an iwi-initiated and led process.
"Often on the Crown side we found ourselves managing claims processes with one eye and sometimes both eyes on legal or other challenges.
"Our experience with the Central North Island forests proves that this does not have to be the case."
The settlement earned support across the House. National MP Tau Henare said getting Maori to bring settlement proposals to the Crown was "brilliant".