A new study has found almost twice the number of people who served in Vietnam have been admitted to hospital with alcohol related mental disorders, compared to people who didn't go to the war.
The University of Otago research studied 3394 men and women who were in Vietnam between 1962 and 1971.
The research looked at hospital admissions between 1988 and 2009.
It reported the alcohol problems mostly related to post-traumatic stress disorder.
Associate professor in occupational health David McBride said the figures for Vietnam veterans showed 89 were admitted to hospital with alcohol problems, during the period.
He said in the general population that figure would be 47.
Professor McBride recommended introducing a 'veteran flag' into national health databases, to better manage veterans' health problems.