New Zealand’s Tower has received 4810 claims after unprecedented flooding hit upper parts of the North Island, including Auckland, last month.

The insurer today maintained its full year earnings guidance and said it expects to make use of its reinsurance cover, which has an excess for catastrophe events of $NZ11.88 million ($10.83 million) - comfortably within its annual $NZ30 million ($27.34 million) large event allowance.

Tower revealed 3600 of its customers had lodged claims: 2660 related to home insurance, around 740 for motor, and the balance mostly contents insurance claims.

“Claims predominantly relate to damage caused by flooding with some related to landslides,” the insurer said.

Tower expects to receive further claims but says the number of lodgments has “slowed significantly”.

A record deluge averaging 250mm struck Auckland, New Zealand’s largest city, on January 27. The deadly weather event, in which flash flooding killed four, is expected to be the largest ever weather-related claims event for the country, the Insurance Council of New Zealand (ICNZ) says.

CFO Paul Johnston says Tower’s “robust” reinsurance has multiple levels of cover and offers protection from the “volatility of large events”.

“We are continuing to assess the financial impact of this event. At this early stage we expect it will trigger Tower’s reinsurance cover for catastrophe events,” Mr Johnston said.

CEO Blair Turnbull says Tower remains financially strong with the “operational resilience to process and manage surges in claim volumes without adversely impacting normal business”.

“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,” Mr Turnbull said.

Tower's reinsurance arrangements provide for house, contents and motor losses, as well as $NZ934 million ($851.46 million) catastrophe cover. Only one excess will be paid for the flood event, which spanned several days, as it is considered to be one event from a single weather system, Mr Johnston said.

Tower, which will provide a further earnings update on February 28, expects to buy reinstatement cover to retain full levels of catastrophe protection. That cost would be absorbed within the current financial year.

Last year, the ICNZ says New Zealand’s extreme weather insured losses hit a record of around $NZ350 million ($319 million). Some analysts have estimated the Auckland flood losses could almost triple that figure.

IAG has received more than 15,000 claims from the event and estimates its gross costs will top $350 million.

Extreme weather does not include earthquake. The Canterbury earthquake sequence of 2010/2011 cost private insurers more than NZ$21 billion ($19.14 billion) and the Earthquake Commission (EQC) $NZ10 billion ($10.97 billion).