A scathing assessment highlights an outdated, potentially earthquake-prone, unsafe and failing Defence Force estate.

Photo: RNZ / Tracy Neal

RNZ has obtained a briefing document to Defence Minister Ron Mark in September last year signed on behalf of Defence Chief Kevin Short that says much of the estate - camps, buildings, roads and water infrastructure - is old and outdated with 41 percent of it barely meeting or failing to meet functional requirements.

The document said barracks were in urgent need of investment at Burnham, Ōhākea, Waiouru and Trentham.

"Particularly those not meeting the minimum living standard," it said.

The report went on to say there were "a total of 47 potentially earthquake-prone buildings across the country".

More pressing, however, was the fact 328 buildings were nearing the end of their operating life.

"These buildings are experiencing rapid degradation of roofs and external cladding, and may also pose a health and safety risk."

The report also noted water networks, fencing, roading and electrical networks that were "in poor to very poor condition".

Photo: RNZ / Phil Pennington

The document warned as the infrastructure reaches the end of its operating life, maintenance costs "will accelerate for limited improvement in condition".

Overall, 78 percent of the estate needs to be replaced in the next 30 years, it said.

The Defence Force has a plan to pump money to upgrade and replace buildings, facilities and infrastructure in the coming decade at its various bases. At last estimate that was at more than $1.7 billion, however that may rise depending on costs for labour and materials.

Defence Minister Ron Mark has previously said he inherited nine years of delays from the previous National-led government.

However, he said military estate had been neglected for decades and he was refreshing the plan and approach to that this year.

Mr Mark said that would focus on immediate as well as long-term needs.

A capability plan looking at the future needs of the military is also due next month.

Along with the pressing estate upgrades, the military plans to spend billions on upgrading and replacing old and outdated planes, ships and other equipment.

National Party defence spokesperson Mark Mitchell said his party had a plan to revamp old property when it was in power.

He said the minister, Ron Mark, needed to commit to that plan to get the work done.

"He keeps reviewing everything - I think it is a delay tactic. He just needs to stump up (and) restate his commitment to our plan.

Read the full redacted document: