According to the Australian Securities and Investment Commission, up to 80% of Australian households are underinsured. That means their total insurance coverage is less than the realistic cost to rebuild the property.
In such cases, if the property is destroyed, the homeowner will need to pay for the additional repair/replacement costs.
However, underinsurance can also reduce the payout when only part of the property is damaged. If you have not insured your house for its full value, your insurer may have the right to reduce any payment in proportion to the level of underinsurance.
This example shows the impact of underinsurance on a house after a storm.