Tower has taken the Earthquake Commission to court over how much it will pay on claims resulting from the Christchurch earthquakes.
The listed insurer and fund manager is disputing EQC's position, which has the effect of limiting claims to a maximum amount in any policy year.
It says if that's correct, the EQC limits do not apply per event and are a maximum aggregate limit in a policy year, unless a payout has been made.
The EQC has classified 10 separate earthquakes in Canterbury since 4 September as separate events for insurance purposes.
It will pay up to $100,000 per house and up to another $20,000 for contents, while private insurance companies cover any further damage.
Tower provided more than $350 million to cover claims from the quakes in its half yearly accounts.