Centralising IT doesn't seem to achieve the right outcomes, each department has its own independent requirements. The main aim should be to interface with a common platform.
Shadow minister for the digital economy Ed Husic said the Government was trying to blame public servants for the increasing costs, rather than taking leadership.
Mr Husic, who led Labor's calls for the Senate inquiry, said the Government did not have enough "digital literacy" to turn the problem around.
"You can see the scale of this when you measure the cost of the digital spending against what is being spent on Newstart payments," he told the ABC.
"The ATO website has been crashing repeatedly over the course of the last six to eight months, and no senior minister has thought it important to step forward and explain what has gone wrong.
"This is a symptom of a broader IT problem in Government."