The Government has confirmed more money will be returned to two of the biggest iwi, under a special Treaty of Waitangi clause.
Ngai Tahu and Waikato-Tainui negotiated a 'top-up' mechanism at the time of settlement, called the Relativity Clause.
The clause kicks in when total Treaty settlement spending throughout the country breaches $1 billion spread between 1994 and 2044.
It means the tribes are entitled to a payment equal to a percentage of any Crown settlement spending above that figure.
For Ngai Tahu, there will be a cash amount equal to 16.1%, valued in 1994 dollars.
For Waikato-Tainui, it's 17%.
A spokesperson for the office of the Minister of Treaty of Waitangi Negotiations says it's possible that the top-up could be activated this year.
Ngai Tahu kaiwhakahaere (general manager) Mark Solomon says the tribe expects the mechanism to be triggered this year or next year at the latest.
He says the deferred payment will benefit all of the South Island economy, where the iwi's investments and distributions are largely focused.
The Relativity Clause was negotiated to ensure the tribes' position is maintained relative to other tribes that settle.