The Government is proposing a change to the definition of serious harm in the Health and Safety in Employment Act, to simplify the reporting of workplace injuries.
At present, the definition covers death, serious injuries such as amputation, crushing and burns, and some other severe conditions.
The proposed change divides serious harm into three categories, including trauma injury which leaves a person unable to perform normal duties for 10 days or more.
Labour Minister Kate Wilkinson says the changes will mean employers won't spend too much time dealing with minor matters.
Engineering, Printing and Manufacturing Union national secretary Andrew Little says minor injuries can often be a sign of a dangerous workplace and it wants more consultation over the changes.