Insurer Vero is calling for debate on whether change is needed to New Zealand's natural disaster insurance model following frustration over the lengthy delays in insurance payouts for the Christchurch earthquakes.

It's released an independent Deloitte report today that provides an overview on the social consequences of the earthquakes and the impact of insurance payments from the time of the first earthquake in 2010 to 2025.

Vero, part of Australia's Suncorp Group, received 31,050 claims relating to the 2010 and 2011 Canterbury earthquakes valued at just under $4. 8 billion and has settled 80 percent of those by value. But figures released by the Canterbury Earthquake Authority today show while insurers have made good progress settling claims in the past year, only 43 percent of overcap claims are yet to be settled and new claims are continuing to come on to insurers' books four years on from the quakes.

Under the dual claims management model those making claims had to deal with the Earthquake Commission which covers the first $100,000 on personal property but any amount over that EQC limit - the so-called overcap - was dealt with by private insurers. And there were further delays where policy responses and damage assessments differed between the EQC and the insurer who had to agree on who would manage the claim.

Vero executive general manager claims Jimmy Higgins said the inefficiency of the dual claims management model had a significant impact on timely payout of claims for customers and it was important to get it right for the future.

"In a natural disaster there is no shortage of good intentions by all players involved in disaster recovery but we need to make sure the system is efficient and works for customers. The question is whether having both an insurance company and EQC management claims is the right approach," he said.

Higgins said customers have said they'd prefer to deal with just one entity when making a claim and Vero thinks it would work best if that entity was a private insurer. It has built up considerable knowledge and experience on how to deal with claims from this type of event that will mean it will do a better job next time around, he said.

Vero's decision in early 2013 to take over management of overcap claims helped reduce processing times with the percentage of claims settled doubling in the past 18 months, the report said. It also found the more rapidly a claim was paid by insurers, the more rapid the return to normal patterns of economic activity.

Higgins said Vero wanted debate on improving the dual claims management model included in the Treasury review of the Earthquake Commission Act which appears to have gone on the backburner since first being announced in 2012.

EQC Chief Executive Ian Simpson said Vero's call reiterates the revisions and improvements EQC has sought to the scheme and insurance response, as stated in EQC annual reports.

"Under the current arrangement, EQC is managing 85 percent of the domestic property claims arising from the Canterbury earthquakes, while private insurers handle just 15 percent of them. Were private insurers to lead on all claims, they would have had to complete six times more assessments than they eventually did," Simpson said.

Earlier this month, Earthquake Recovery Minister Gerry Brownlee said the review was almost completed and a report will likely go before Cabinet in the next month or two, with only minor changes expected to be recommended.