The Government has declined to open its treaty settlement books as a top-up clause for Ngai Tahu and Waikato-Tainui draws near.
Both iwi negotiated relativity clauses as part of their settlements, entitling them to a percentage of all future settlements once they exceed $1 billion.
When the $1 billion mark is reached, Ngai Tahu would be entitled to 16.1% of future settlements, and Waikato-Tainui 17%.
The Office of Treaty Settlements declined to release the latest relativity clause statement, which the Otago Daily Times requested under the Official Information Act.
Director Peter Galvin confirmed the clauses were likely to be triggered in the next one or two years, and the latest statement "does not differ significantly" from the previous period.
"As we draw nearer to the triggering of the relativity mechanisms, the need for confidentiality among the parties to the relativity mechanism contracts increases."
Relativity clauses were calculated in 1994 dollar terms, adjusted for interest and inflation, and were last calculated at $787 million in 2008-09.
In February 2010, treaty claims passed $1 billion in nominal dollars, and the ODT has calculated a further $280 million in settlements have been signed since that date.
For the purposes of the relativity mechanism, a settlement of $50 million in the 2008-09 financial year is equivalent to a settlement of $24 million in 1994.
• The Government has rejected a Far North iwi's proposal for a partial Treaty of Waitangi settlement, but iwi negotiators are confident the door remains open for future claims, NZPA reported.
Ngati Kahu is one of five Far North iwi with overlapping interests which last year signed an agreement in principle that would form the basis for future settlements with each individual iwi.
The iwi recently presented a draft settlement to the Crown seeking a partial settlement, rather than a full and final settlement, as set out in the agreement with other iwi.
Treaty Negotiations Minister Chris Finlayson said the Government's policy was to reach durable and comprehensive settlements, not partial settlements that allowed grievances to linger.
