Public service a large and complex beast

The head of the federal government's digital transformation team may have come from one of Australia's big four banks, but its size and complexity pales into insignificance when compared with the Australia Public Service.

Digital Transformation Agency chief Gavin Slater took up the role last year after 17 years with the National Australia Bank, an organisation he felt was large and complex with 44,000 employees at its peak.

"It is nowhere as large and complex as the APS," Mr Slater told a Senate hearing on Tuesday.

"Coming into the APS, we have got over 137,000 people working over a range of policy and delivery agencies, it is far more complex than anything I have had to deal with."

He said the public service was extremely decentralised, with every agency having its own secretary and executive team accountable to its respective minister.

They also each have their own HR, finance and technology functions.

"So in a way, each one, while connected under the umbrella of the APS, at times feels like a different organisation, so that adds to the challenge and complexity," he said.

The role of the agency is to improve access for people to government information and services.