The package for some Southern Response policyholders could cost $313 million, if all those eligible apply.
Southern Response is the government-owned company responsible for settling claims by AMI policyholders for Canterbury earthquake damage.
In December, Minister Responsible for the Earthquake Commission David Clark announced a package for claimants who settled their claims before October 2014.
It comes after a landmark case in the High Court, which found Southern Response misled and deceived Karl and Alison Dodds. The couple had accepted an offer almost $200,000 lower than a secret higher estimate to fix their house, despite having the 'best insurance policy money could buy'.
The package offers a top-up payment to customers in a similar situation, with payments including professional fees, a contribution to legal fees, unpaid contingencies, and interest.
"Southern Response has been working with its actuaries to estimate payments likely to be made under the approved package. We are now in a position to release the cost estimate of the full package," Clark said.
Based on actuarial advice, Southern Response is including a cost of $242.5m in its accounts, reflecting an estimate of about 75 percent take-up of the package.
Clark said some eligible customers may have moved overseas or change their details since but Southern Response would continue to look for their contact information if they were eligible.
"Southern Response is preparing an extensive advertising and direct contact campaign to reach out to as many people as possible, if court approval is given."
The package may also potentially affect those people who are part of the Ross class action law suit, and Southern Response is seeking court confirmation that it can communicate with those policyholders about the package.
Clark has also today released the papers that establish the package.