While the vast majority of APS leaders, the elite 'Senior Executive Service' are still based in the ACT, the proportion of federal public servants working in the territory has shrunk by 7800 since 2013, or about 12 per cent.

In the same period the overall number of public servants has declined by 8.3 per cent

The figures, from the latest statistical bulletin from the Australian Public Service Commission, come as National Party politicians pile on the pressure to move more government workers out of Canberra and move them to Nationals-held seats in rural and regional Australia.

Deputy Prime Minister Barnaby Joyce has been blunt about "decentralisation" being "core business" of the government and that more of the policy should be expected.

The Nationals Leader is using a parliamentary inquiry, forced by Labor and the Greens, into the controversial move of the pesticides authority from Canberra to northern NSW, to drum up support for moving more departments and agencies to the bush.

But Canberra's local territory and federal politicians from both major parties are aghast at the plans to move the Australian Veterinary Medicines and Pesticides authority to Armidale, in the heart of Mr Joyce's New England seat, and at further erosion to numbers in the APS, easily the ACT region's largest employer.

The ACT Government expressed alarm at the idea of more public servants heading out of the capital, with the territory Labor Chief Minister Andrew Barr saying in his submission to the inquiry that the federal public sector was vital to the economic wellbeing of more than 450,000 people in Canberra and the surrounding region.

The Chief Minister wrote that the ACT region, including with the surrounding local government areas of Yass Valley and Queanbeyan Palerang was home to more than 450,000 with about 20 per cent of workers from the NSW south-east and tablelands relying on job opportunities in the territory itself.

"More than one-third of that workforce is employed in public administration meaning that the direct and indirect implications of Commonwealth job cuts do not only seriously harm the ACT economy, but also the workers and businesses in the surrounding regions that rely on those jobs," Mr Barr wrote.

He wrote the Armidale move is "another instance of Commonwealth employment decisions made without regard for the consequence of the ACT economy or the workers and businesses in the Canberra region that significantly rely on the economic activity underpinned by public sector employment."

Liberal Senator Zed Seselja wrote in his submission that he too was worried about the local economy if more public service jobs were lost or forced out of town.

"To move public service agencies out of Canberra will have a far more consequential effect on the local economy than elsewhere in Australia," Senator Seselja wrote.

"The consequences are far wider than the raw job numbers in the public service, though, with thousands of people working in small businesses around Canberra who assist and serve the public also having their livelihoods threatened by agency moves."