A study has put the cost of drug and alcohol abuse at $6.8 billion a year, equivalent to the entire output of New Zealand agriculture.
The research, carried out by the economics consultancy BERL for the Ministry of Health and the Accident Compensation Corporation, said three quarters of the damage is done by alcohol and the remainder by other drugs.
BERL senior economist Ganesh Nana said most of the cost is lost output from people who would otherwise be more productive or employed for longer.
Other factors include resources diverted into producing illegal drugs which should be used for other things, health costs and the harm caused by crime and road accidents.
Ganesh Nana says many aspects of the research are hard to pin down, such as separating lost production from substance abuse compared with other factors such as a person's level of skill in the first place.
To cover for this, he says, conservative assumptions were made in the research. The study uses figures from 2005 and 2006.
