"If we divide ourselves up into something like eight or nine regions, now that our upgrades have rolled through most of those regions, all but three of those regions are now within the target," Monaghan said. "The ACT, which is currently going through the upgrade process, has a substantially larger backlog than that and, as soon as the system stabilizes, with help from industry, the staff will get on and roll those back."

Senator Bishop then asked what was the backlog in the ACT and Monaghan said "in the order of 5000," which is about 30 percent.

Monaghan claimed a number of causes for this backlog in the ACT, one being the difficulty of retaining IT staff within Defence and "therefore they are under pressure."

"Primarily what we have done is diverted the attention of those staff from delivering standard support to supporting the rollout of the new systems," he said. "We are getting close to completing that program. As soon as we do, they will be turning their full attention to reducing the backlog to a reasonable level."

Defence expects to see the backlog "vastly improved" by the start of business next year.