Insurers are often overly influenced by strategic portfolio implications when making decisions on earthquake claims, according to a Marsh study.

The report examines the impact of three of the four most devastating quakes in history: Chile, February 2010; New Zealand, February 2011; and Japan, March 2011.

It says insurers may be wary of setting precedents for claims relating to the same event or may be concerned about exposures on different earthquakes.

“The challenge is to get insurers to treat a client as a client, and not as part of their portfolio, although this can be easier said than done,” the report says.

There are also “slightly concerning messages” about the influence reinsurers have on the claim process.

The Chile quake killed 562 people and caused $US8.4 billion ($9.31 billion) of insured losses and $US30 billion ($33.25 billion) of economic losses.

The New Zealand event cost 185 lives and caused $US15.3 billion ($16.96 billion) of insured losses and $US23 billion ($25.49 billion) of economic losses. In Japan 19,135 people died, insured losses hit $US35.7 billion ($39.57 billion) and economic losses were $US210 billion ($232.75 billion).

Settlement times varied, with many claims still outstanding in New Zealand due to issues such as “the closure of the CBD, ongoing earthquake-related activity and practical difficulties in assessing the scope and nature of damage”.

New Zealand was also the least prepared of the three countries, the report says. Previous events had not hit such a large area and Christchurch was not considered a high-risk zone.