The computer issues which plagued the rollout of the national disability insurance scheme could have been prevented if live testing was undertaken, a Senate committee has been told.
But the department in charge of the scheme's policy says the IT issues weren't a "massive system failure".
The federal government commissioned a review into the glitches affecting the MyPlace portal after problems with the uploading of provider data delayed payments to providers and participants.
The Department of Human Services admits that live testing of the system would have prevented the glitch.
"We obviously would have picked up on some of the issues earlier," official Gary Sterrenberg told the Senate estimates hearing in Canberra.
But Mr Sterrenberg said live testing would have made it difficult to control who would have access and it wasn't a departmental practice to use live participants.
"If we had asked a small group of users to log on that would have obviously highlighted the issues earlier," he said.
"Going forward... we'll seek to find ways to do that testing."
However, the Department of Social Services played down the glitch saying the system did not suffer outages nor was ever shut down.
Secretary Finn Pratt said the problems were not anticipated, but any big IT build would have a number of flaws.
"But essentially the IT did what it was meant to do," he said.
"There was no outage. This view that there was this massive system failure is not born out by the evidence."
