Finance Minister Bill English says a court ruling on insurance claims in Canterbury could add up to $1 billion to costs faced by the Earthquake Commission.
In a declaratory judgement, the High Court has found that the Commission is liable to cover multiple disaster claims on one property.
Mr English is waiting for more advice on how it will affect the Crown's liability - the amount expected to be paid out in claims.
He says it could be up to $1 billion extra, but he hopes that figure is the worst case scenario.
Last week, EQC revised the amount it expects to pay out in claims upwards, from $3.05 billion to $7.07 billion, but that was before the court's judgement was released.
