House and contents were the biggest areas of claim with $15.48 million so far in the first six weeks after the storm.
Since the January storm there has been two other major storms hit New Zealand with ex-tropical cyclone Fehi hitting last week and ex-tropical cyclone Gita causing havoc in the top part of the South Island earlier this week.
Grafton said it was too soon to know what the costs of those storms would be.
But he warned major storm events were likely to become more frequent and more severe and urged the country to make changes to minimise the costs of these events.
"The cost of this storm so far demonstrates the importance of adapting to climate change and putting processes and infrastructure improvements in place that minimise the costs and impacts of these events," he said.
"As time goes on, we expect these sorts of events to become both more frequent and more severe. Every dollar spent on adaptation now will be more than repaid in future savings."
Last year was the most expensive year on record for weather-related insurance losses in New Zealand with a total insured-losses value of more than $242 million.
The most expensive event of the year was Cyclone Debbie, which hit in early April and resulted in 5,470 claims totalling $91.5 million in insured losses.