New Zealanders are likely to have significantly under-insured their properties to the tune of tens of millions of dollars.
Auckland-based residential property finance company General Finance believes up to 20 percent of homeowners could be affected.
A director, William Cairns, said the method of assessing housing insurance had changed and unless people look at the detail when renewing policies, they may find themselves seriously out of pocket if they have to rebuild their houses after a calamity.
He said people should check their policies every three to four years.
"Building costs change and consent processes change, so it needs to be regularly done," he added.