The defence force says it is moving to upgrade its weapons stores after an internal report found much of its $155 million of ammunition and explosives was stored in old or leaky warehouses.
The Defence Ministry report said most of the storage space for ammunition and explosives was in poor condition.
The navy's Kauri Point bulk ammunition store on Auckland's North Shore was singled out because its leaky roof led to $121,000 worth of naval shells being written off because of water damage.
Ministry spokesman Commander Shaun Fogarty said work had started on fixing the problems outlined in the report, which was written last year by the defence force's evaluation division.
"New Zealanders can rest assured it's not something we're ignoring," he said. "Steps are being taken to address the leaky roofs. Some have already been replaced and others are due to be replaced."
A 2005 Navy report found that of 41 explosive store houses at Kauri Point - which is the entry point for most shipments of bulk ammunition for the Navy, Army and Air Force - only two were in good condition.
The remainder were classed as fair (9), poor (27), or very poor (3).
Mr Fogarty said there were plans to build a new security fence around the Kauri Point facility "in the near future".
He said long-term plans to improve storage facilities would be reviewed over next few months, with any work to be completed by the end of the year.
All but five of the ministry's 120 bulk explosives storehouses were built in World War II or earlier.
Mr Fogarty said that eventually all the old ammunition and explosive stores would be replaced by new buildings.