Police believe his firearm discharged while he was crossing a fence.
Ms McKee said while few details had emerged of the two incidents, both fatalities were unnecessary. The teenager died during the second weekend of the duck hunting season, a popular New Zealand past-time, Ms McKee said.
"Not knowing the details of what occurred yesterday morning it's hard for us to specifically point to what might have gone wrong," she said. "Going on past tragedies and injuries that have occurred it sometimes mostly relates to loading a firearm before they need to, and not looking at their firing zone when they fire their shots."
Ms McKee said the 21-year-old was understood to have died from a rifle shot, so was likely hunting big game. She said all hunters were told to completely unload their firearms before crossing fences and any other obstacles.
"It need not have occurred if all firearms were completely unloaded at the time of crossing the fence," she said.
Ms McKee said there were seven rules for firearms safety, and almost all firearms fatalities can be traced back to one rule being broken.
"[Hunters] need to remind themselves that they've got a tool in their hand that can deliver lethal force not only to the animals that they're after but to others as well... I sometimes suspect that complacency plays a big part in this."
