The Coalition wants to shift more than 120 public service jobs from the capital in an expansion of its policy of moving the bureaucracy to the regions.

Other planned changes to the public service include shifting bureaucrats into state government agencies on secondment, and further cuts to the Human Services Department.

Canberra is the main target for the Coalition's decentralisation plans: it is the main source of most positions marked for relocation.

Of the 190 jobs to go bush in 2019-20, the ACT would lose 35 jobs from the Department of the Prime Minister and Cabinet, 10 from Indigenous Business Australia and others from the Australian Financial Security Authority under a Coalition government.

The decentralisation promises are in addition to the Coalition's plege to move 76 Murray Darling Basin Authority staff from Canberra to Mildura, Goondiwindi, Griffith and Murray Bridge.

Finance Minister Mathias Cormann backed the project, saying more than 1700 jobs had moved from Canberra, Sydney and Melbourne since the Coalition came to power, and 1000 had gone to the bush.

"The government continues to consider where it would make sense for public sector employment opportunities to be further extended to regional Australia, as part of future policy-making," Senator Cormann said.

Nationals leader Michael McCormack and his deputy, Decentralisation Minister Bridget McKenzie, said the "practical, planned" relocations would support regional growth and connect agencies better with their clients.

Non-military government staffing is projected to grow for the second consecutive year, increasing by 1300 to 166,762 in 2019-20.

Despite the election-fuelled spending, the size of the government, relative to the population, is expected to shrink marginally over the coming year.

The growth in the government's staffing is driven partly by the planned swelling of the Tax Office's ranks by nearly 700 jobs, although the agency's staffing would still be lower compared to last year's forecast for 2018-19.

The Home Affairs Department would gain more than 400 staff, and Defence would add more than 260 after a cut last year. The Department of Foreign Affairs and Trade will add another 200 public servants.

Among the losers is Agriculture, shedding 200 staff, while the Health Department will lose jobs under a restructure of the bureaucracy. The Human Services Department, overseeing Centrelink, will shrink for another year as it cuts another 200 public servants from its ranks.

While the government justified its average staffing level cap as a necessity until the budget was back in the black, the return to surplus hasn't led to a wholesale surge of public servant numbers.

Senator Cormann used the budget to announce the Public Service Commission would pilot a new program in 2019 seconding federal bureaucrats to state and territory government agencies, businesses and not-for-profit groups.

"Enhanced mobility will allow the public sector to draw on a broad base of experience when developing programs, designing and delivering services for citizens, and providing advice to the government," he said.

New spending on the public service outside of security and tax crackdowns is mainly for IT projects, with the Australian Bureau of Statistics to receive $38 million for the 2021 census to ensure there is no repeat of the 2016 census debacle.

The Australian Electoral Commission will also be funded to scope the market in a bid to replace its ageing IT infrastructure. Costing $10.8 million over the next two years, the commission is looking to deploy new polling-place technology as well as the platform that houses the electoral roll.

After the hacking of parliamentary email systems as well as the Liberal and Labor parties' IT networks, an undisclosed amount of money will be spent across the government to secure government technology before next month's election.

Extra jobs are on the way for the Office of the Information Commissioner, with 35 positions to bolster responses to privacy complaints and enforcement actions against social media and other online privacy breaches.

The budget papers also say the Commonwealth integrity commission will be up and running on January 1, 2020, with 39 jobs assigned to the long-debated watchdog.