The Defence Minister has ordered a wide-ranging inquiry into safety standards in the military, prompted by the drowning of a soldier in September 2012.
Private Michael Ross fell overboard during a training exercise on Lake Moawhango near Waiouru.
Although the full court of inquiry has not yet been made public, it has already emerged that Private Ross's lifejacket failed to inflate.
Dr Coleman said on Thursday the family of Private Ross can be completely appalled at the multiple failures that led to the drowning and there are enough worrying elements about the case to merit a closer investigation.
"What I have asked for is a wide-ranging inquiry into the culture of safety in the procedures in the Defence Force when bringing in people from outside as well as military experts because I think the public and, frankly, our serving personnel and their families need assurance that the Defence Force has got it right."
Dr Coleman said he also needs an assurance that the Defence Force doesn't have systemic health and safety problems.
He said the Ross case is not the only one that has raised alarm, citing the Air Force helicopter crash on Anzac Day in 2010 in which three people died and one person was seriously injured.
The minister said the inquiry would report back within weeks.
The Defence Force faces sentencing in July for failing to take practicable steps to ensure the safety of Private Ross and could be fined $250,000 as punishment.