Commonwealth government spending on IT contractors is "eye watering", according to the public service's outgoing tech guru.
But the public service's "remarkable" over-dependence on outsourcing creates "perverse outcomes" and a culture of "blame aversion", departing Digital Transformation Office chief Paul Shetler says.
Mr Shetler has written that the history of the federal government digital failure underlines the need for the public service to train its own workers and end its reliance on expensive and wasteful private sector outsourcing.
Mr Shetler also fired a parting shot at the Canberra mandarins who were resisting change and needlessly complicating the digital transformation agenda.
The former Chief Digital Officer for the UK Ministry of Justice who raised eyebrows in Australian Public Service by wearing sneakers to work, led Prime Minister Malcolm Turnbull's pet public service project, the Digital Transformation Office, from July 2015 until it was re-launched and renamed in October with career public servant Nerida O'Loughlin at the helm.
Mr Shetler was in his new job of Chief Digital Officer for less than six weeks before he resigned in late November.
But in a parting address published on LinkedIn, he said that government's digital challenge was not always as daunting as public servants and politicians claimed.
"When it comes to service delivery, the transaction volumes of government services are small compared to the wider world," Mr Shetler wrote.
"Government might think it's huge, but its daily transaction volume is equivalent to just a few minutes of Twitter – or even less on the NASDAQ.
"And still, government spends more than $16 billion a year on IT.
"Our procurement and funding processes encourage big IT programmes, with bigger contracts.
"They drive a culture of blame aversion which create the perverse outcomes and actually increase risk.
"The history of the past several years of government IT failure is testimony to that.
"This is further complicated and exacerbated by the lack of technical and contract management expertise in government.
"Too frequently, we actually ask vendors to tell us what they think we should buy."
Mr Shetler wrote of how the public service had been stripped of its technical skills by decades of reliance on private sector contractors.
"There's also a fear of digital," he wrote.
"Over the last 40 years, as we've outsourced technology, there's been a progressive de-skilling of the public service.
"The reliance on consultants is remarkable and the amount spent on them is eye-watering.
"That's just not necessary if we re-skill the public service, which was one of the Prime Minister's goals on establishing the DTO.
"Government's biggest challenge in the digital age is to completely upskill the public service so that it is well equipped to deliver the change that's needed."
Mr Shetler wrote of the many public servants who were working hard to improve the services they provided but "institutional inertia" and resistance to change remained serious problems.
"All of their work is made more difficult by the astonishing complexity across government," Mr Shetler wrote.
"I've sat in meetings where senior public servants search out the exceptions and the edge cases – at the expense of simplifying the common case, because they're focused on the process rather than a better outcome.
"It's naive to expect an organisation that is very comfortable with its way of working to decide to spontaneously transform itself."