Tower Insurance has received more than 4800 claims over the catastrophic floods in Auckland and expects more to be lodged.
The insurer said 3600 customers lodged claims, with 2660 of the claims for home insurance, 740 for motor vehicles, and the rest mostly contents.
The number of claims had slowed significantly but the firm was still expecting more to come in.
It was continuing to assess the financial impact of the event and expected the floods to trigger the company's reinsurance cover for catastrophic events.
Its excess for such events stood at $11.9 million, which was below the $30m the company allowed for large events in 2023.
Chief executive Blair Turnbull said Tower remained financially strong with robust reinsurance cover.
The company also had operational resilience to process and manage surges in claim volumes without causing major disruption to normal business, Turnbull said.
"Tower continues to invest in sophisticated underwriting capabilities and risk-based pricing which enhance our rating agility and accuracy and help to deliver sustainable margins," he said.
Chief financial officer Paul Johnston said Tower's reinsurance arrangements provided $934m of catastrophe cover.
"In line with Tower's comprehensive approach to reinsurance, it is likely we will purchase reinstatement cover to ensure we retain our full levels of catastrophe protection, with the costs for this being absorbed within the financial year," Johnston said.
Tower's 2023 full-year guidance remained unchanged.