Professor Wilson, of the University of Otago, said some international studies have not recorded the same drop in life expectancy, something he attributes to the 'healthy soldier effect'.
"This effect arises from healthier men being selected into the military to start with – and with less healthy men being rejected at the recruitment stage," he said.
He said the results of the latest study are preliminary - as they are based on data from only 702 veterans, all of them buried in one large New Zealand cemetery.
"It is possible that these men, who were buried in the Taita Lawn Cemetery in Lower Hutt, were not typical of all New Zealand veterans.
"That is, if they had been disproportionately from lower socio-economic groups, then some reduced lifespan in this group might have been expected regardless of war participation.
"Nevertheless, from what we know of the socio-economic makeup of the Hutt Valley population, we think that any such effect may be small," Professor Wilson said.
Co-author Professor Glyn Harper said there is a need for a much larger study covering WWII veterans from all over New Zealand.
"New Zealand society needs to fully understand all the dimensions of one of the most important events in New Zealand's history and of the 20th century," he said.
Professor Harper, from Massey University, said the initial findings from the study are not surprising given that previous New Zealand research has found a high level of long-term health problems in World War II veterans.
The 1995 book Silent Casualties – New Zealand's Unspoken Legacy of the Second World War by journalist Alison Parr, reported that in 1985 more than 10,000 veterans were officially recognised as suffering from 'nervous system disabilities', including cases of post-traumatic stress disorder and alcohol abuse.
Official data shows that in 1946 there were 22,846 WWII veterans receiving war pensions for service-related disabilities.
In the 1945-1946 year the New Zealand Government spent £58,302 on the medical treatment of war pensioners.
