The country's largest insurer IAG New Zealand reported a $105m before tax profit for the year to June 30 and increased premiums to cover reinsurance costs following the Christchurch earthquakes.

The Australian-owned company's profit has rebounded from last year's earthquake impacted $5m result.

IAG which owns State Insurance, NZI and AMI increased its gross written premium by 24.4 per cent to $1.6 billion, up from $1.2b last year.

Premiums increased the most at NZI, but IAG did not provide details of the scale of the increases.

However, insurance margins improved to 10.4 per cent from 0.4 per cent last year.

IAG dominates the market with a 55 per cent of the home and contents insurance and 60 per cent of private motor insurance.

New Zealand chief executive Jacki Johnson said the result was solid in a challenging market.

"The underlying performance of our New Zealand business has remained strong" and the result was a "substantial improvement over the earthquake affected result" last year," Johnson said.

IAG bought troubled Christchurch-based general insurer AMI in December last year for $380m, excluding its $1.8billion liabilities relating to the earthquake which have been taken over by the Government.

The acquisition added nearly 30 per cent to IAG's New Zealand premium base and contributed to the group's growth strategy, Johnson said.

More than $1.3 billion of earthquake claims had been settled at June 30, but residential claims were lagging.

A survey of 1000 Christchurch residents earlier this month revealed the two large IAG and Vero, were regarded as the slowest in tackling residential repair and rebuild claims, leaving many homeowners angry and frustrated.

IAG has built 30 houses and completed 21 over- $100,000 repairs so far, a drop in the bucket of its 6500 repairs and rebuilds.

Customers were being told they faced a wait of up to five years to have repairs completed.

IAG has settled almost 50 per cent of its 13,000 commercial claims

"Settlement of commercial claims is progressing in line with expectations although residential claims have been slower to finalise owing to a range of complexities such as work being completed on land zoning, land remediation, and repair methodologies being developed," Johnson said.

IAG reported a group result of A$207m [NZ$268m], down from A$205m last year.

- © Fairfax NZ News