The ministry that includes the former Department of Labour has promised it will investigate any future crashes of military aircraft.
Air Force Flight Lieutenant Hayden Madsen, Flying Officer Dan Gregory and Corporal Ben Carson died when their helicopter crashed into a hill at Pukerua Bay, near Wellington, in low cloud on Anzac Day in 2010.
State Services Minister Jonathan Coleman is launching a third review of the fatal crash after neither the department nor the Civil Aviation Authority looked into possible health and safety failures by the Defence Force.
A military court of inquiry last year recommended sweeping changes after uncovering an Air Force culture of rule-breaking and inadequately trained squadrons. Dr Coleman will announce details of a review checking up on those changes later this week.
It has now emerged that the then-Labour Department, which has been incorporated into the Business, Innovation and Enterprise Ministry (MBIE) and is responsible for health and safety law, did not investigate the Anzac Day crash because it wrongly believed it was the Civil Aviation Authority's job.
The CAA, however, does not cover military matters. The Government's legal office, Crown Law, has since found that labour officials misinterpreted the law.
Brent Murray, general services manager of the ministry's labour group, told Radio New Zealand's Checkpoint programme on Monday that the mistake is unfortunate.
"Air crashes happen very infrequently and, effectively, the jurisdiction hadn't been tested. We operate under the assumption that we don't investigate air accidents - and that's what I asked for the Crown Law opinion on."
Mr Murray says he has apologised to Andrew Carson, the father Corporal Carson, and in future the ministry's labour group will take the lead in such investigations.
Dr Coleman directed that the State Services Commissioner look at the role of the labour group, the aviation authority and the Defence Force so that the situation does not happen again.
Meanwhile, Andrew Carson says it is incredible that police have not launched a criminal investigation and the latest review will not find out who is responsible.
Mr Carson told Checkpoint on Monday the Minister of Police told him almost a year ago that police would keep him informed, but they have not once been in contact.