The discovery of a glitch in the way official workplace fatalities were recorded has revealed the actual figure is between 20 and 30 per cent lower than previously thought.
Statistics New Zealand today said an error in the way fatal work-related injuries were recorded meant in some instances one fatality was counted multiple times, pushing the figure incorrectly high between 2002 and 2012.
The error happened when a workplace fatality could be possibly attributed to more than one injury to different parts of the body.
"As some deaths result from multiple injuries, the number of deaths reported in earlier publications was too high," said Statistics NZ in a statement.
The figures are used to measure national injury trends.
However, the work-related injury figures for fatal and non-fatal injuries in the workplace were not published in December 2012 because of concerns about their accuracy raised during quality assurance processes, said spokesman Steve Manning.
A review of the data found the real figure for fatal work-related injuries between 2002 and 2010 were on average 20 per cent lower than those previously published.
Since 2010 the new figures were an average of 30 per cent lower.
The error did not affect the non-fatal work-related injury indicators, and there were no concerns any other data had been affected, said Mr Manning.
The problem has since been corrected so the number of fatalities, rather than the number of injuries, is counted.
Data for fatal work-related injuries have been expanded to include Ministry of Business Innovation and Employment notifications and ACC claims.
The process for identifying and removing occupational disease, illness, and gradual process injury has also been updated.
A landmark report on health and safety this year, which did not use any of the inaccurate information, found New Zealand had an "appalling, unacceptable and unsustainable" record in workplace health and safety.
About 100 New Zealanders die in workplace accidents every year, an annual death toll of about four in every 100,000 workers, the Independent Taskforce reported earlier this month.
That is twice the rate of Australia, three times the rate of Britain, and worse than all six other developed countries.
A further 500 to 800 New Zealanders die every year from chronic diseases caused by workplace conditions, and the Accident Compensation Corporation (ACC) receives about 200,000 claims annually for work accidents.
"We have a system that has clearly been shown to be inadequate," Shell-Todd Services general manager Rob Jager, who chaired the taskforce, said at the time.