Analysis of the pay brackets of every federal department and agency shows salary differences across agencies mean a worker could be earning more than a public servant two classifications above them at a different agency.

The new figures show the gap between the lowest and highest paid public servants in the Executive Level 1 band has grown to almost $53,000, up from around $47,000 four years ago.

Staff at EL1 level are most common in Canberra, followed closely by those working at APS6 level. The $52,647 difference is between the highest paid EL1 at the Australian Institute of Aboriginal and Torres Strait Islander Studies on $98,639 and the highest paid at the Australian Office of Financial Management on $151,286.

At entry level, the two agencies are again at opposite ends of the scale. An entry level EL1 at the Australian Institute of Aboriginal and Torres Straight Islander Studies takes home $89,922, which is $31,107 lower than the lowest paid EL1 at the Australian Office of Financial Management at $121,029.

The data shows workers considering moving to another agency could end up with a pay cut even if they took on a more senior role elsewhere.

This analysis comes as submissions to the independent APS review led by David Thodey focus on a need for the public service to encourage mobility across agencies, and a sense of loyalty to the public service as a whole over a particular department.

The Department of Home Affairs submission said offering staff "a wide variety of career options, and mobility within the APS" would help attract and keep talent. The mega-department also called for a single strategy when it comes to how staff are employed.

"Introducing a single approach to compatible and integrated systems access, security/integrity requirements, and pay and conditions across the APS would allow for agencies to better attract and retain the right people by providing attractive development opportunities, and facilitate more seamless transfer of APS employees across agencies for the purposes of increased collaboration through mobility," the submission said.

The Australian Taxation Office submission said all agencies negotiating their own enterprise agreements within a narrow framework created significant inefficiencies.

"Efficiency gains could potentially be realised by allowing agreements to be negotiated as one or in clusters (potentially by portfolio)," the submission said.

The University of Melbourne's School of Government said fostering a "one APS" culture should be a key focus of the review and an integrated workforce development framework.

It's many years since public servants were paid the same no matter what agency they worked at, and the years-long dispute over the enterprise agreement covering staff from the former immigration and customs departments shows there would be little appetite to change for the status quo, with higher-paid Customs workers unwilling to take a pay cut, and the department unwilling to bump other staff up to the same level.

Many submissions to the review, from individuals, academics and departments, called for increased measures to encourage and facilitate public servants moving between agencies.

The rate at which public servants move around departments has remained stagnant for years, with 71.9 per cent of public servants reporting last year they had worked for just one agency, and 17.8 per cent reporting they had worked for two and around 10 per cent working for three or more.

Dr Samantha Johnson from the University of New South Wales' public service research group said increased mobility around departments had benefits for the workplace and the worker.

"That means you've got knowledge shared, you've got cultural change that can happen when people move around the place and bring different experiences into organisations," Dr Johnson said.

"Which is one of the reasons why senior executives often have had a career that has greater breadth and less depth, because they've moved across different departments, they have different exposure to political realities, to cultures, to organisational ways of behaving, and they take that experience with them."

While financial considerations were a significant factor in people's decisions to change or stay in their job, it wasn't the only factor, Dr Johnson, who specialises in public sector leadership, said.

"It's not the be all and end all, you can't be black and white about this. There are many people who will put the financial aspects aside and they will move to develop a career as they choose and their pay will go up a bit and down a bit, and they won't be too worried about it," Dr Johnson said.

"But there are other people who will find it more difficult and be more reluctant to move if they believe that the financial loss is too great, then it can be an inhibitor."