Tower is raising insurance premiums by up to 30% after the company increased its reinsurance coverage.
The company says premiums for its house, contents and motor policies will go up to offset increased costs.
The insurer and fund manager has reinsurance cover for two catastrophic events.
The excess for an event occuring this financial year has increased to $11.7 million compared with $6.7 million in the previous year.
Group managing director Rob Flannagan says the excess is what the company can afford to carry without eroding its capital.
"The company is in very good shape financially, it's very strong and it's trading well, so we think it's appropriate just to increase our excess, mainly to reduce the cost of the reinsurance."
Tower says it has enhanced the reinsurance programme, with a limit increasing to $525 million per event.