NZ Defence Force websites have now been offline for nearly a week - but the military says a hardware failure is to blame, not ransomware or a bid by China's PLA to steal blueprints for our combat tractors.

The amateur blogging site Medium.com is being used to host Army, Navy and Air Force sites while a fix is underway.

At this point, there is no estimated time to get everything running again.

"A hardware failure affected storage at one of our data centres, which has meant the NZDF, Navy, Army and Air Force websites have been inaccessible since earlier this week," an NZDF spokeswoman told the Herald.

"We have been working alongside the manufacturer on the problem."

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While Medium.com is being used as a stop-gap, "We're working on an alternative hosting arrangement in case the issue with the hardware cannot be resolved easily and quickly," the spokeswoman said.

The outage has lasted since Monday.

It affected a storage array and automatic failover was not available, the spokeswoman said.

"NZDF has a number of information initiatives being evaluated for funding. Our online presence and associated infrastructure is part of this," she added.

Microsoft and Datacom were originally selected, in 2018, to provide a proof of concept cloud-based platform for NZDF to help inform a more detailed investment case and strategy.

Cabinet recently approved modernisation of NZDF's core IT infrastructure, based on an Enterprise Cloud Capability. This is being undertaken in partnership with Microsoft, NZDF said.