The Civil Aviation Authority says it will not be prosecuting anyone over an incident in 2009 which the Air Force put potentially explosive gas canisters on an Air New Zealand flight to Canada.
The authority on Wednesday released an interim report into how the canisters were carried on the flight from Auckland to Vancouver in 2009 when they are not permitted.
Air New Zealand says it was never told about them.
The director of Civil Aviation, Graeme Harris, says the interim report shows significant failings in the Air Force which itself found that the canisters were packaged and labelled incorrectly.
Neither were they made safe for transport with the required safety pin.
The report recommends further investigation into communication processes between the Air Force and agencies such as the authority that were not aware of the incident.
Mr Harris told Radio New Zealand's Checkpoint programme on Wednesday the Air Force has made several changes since 2009 and it has had no further reports of problems involving dangerous goods on civilian planes.
"That was one of the issues we really turned our minds to to begin with ... to assure ourselves that the system was safe and that there was no immediate action required to fill any gaps and we're happy about that."
Mr Harris says the purpose of the authority's investigation is not to blame anyone, but to reduce the risk of something like this happening again.
The Civil Aviation Authority is likely to provide a final report in the first half of next year, along with recommendations for any improvement in the way dangerous goods are carried - especially those of military origin, he says.
The Air Force says it will look at the way it communicates with other agencies.
It says it has almost implemented all of the 22 recommendations from its own inquiry, including new electronic systems, clearer roles and procedures, and staff training.