The embattled Deputy Prime Minister unveiled plans to move Melbourne and Geelong-based public servants from the Department of Agriculture to Darwin as part of plans for a new $8 million "biosecurity hub" in the Northern Territory capital.

Friday's announcement did not include details of how many public service jobs would be moved, the latest part of decentralisation efforts by the Coalition.

"This facility at Berrimah will help us replace some of the work we're doing in Geelong, so we're moving jobs and work from Melbourne to Darwin and that's a good outcome for the north," Mr Joyce said.

But by Tuesday, Mr Joyce's office had backtracked and said no forced moves would take place.

A spokeswoman said jobs in the hub would be new positions and staff at the Australian Animal Health Laboratory wouldn't be relocated.

"There will be no impact on the workload of AAHL given the projected increase in the need for biosecurity diagnostic testing and AAHL's role in doing confirmatory testing as an international reference laboratory," she said.

Liberal backbencher Sarah Henderson, who holds the marginal surf coast seat of Corangamite, jumped on the apparent change.

"AAHL will continue to do confirmatory testing if a local positive result is found in Darwin that requires confirmation.

"The new infrastructure will also protect AAHL from inundation of diagnostic work in the event of a disease outbreak," Ms Henderson said.

"This will ensure AAHL retains its capacity as a critical part of Australia's biosecurity infrastructure and one of the most sophisticated laboratories in the world for the safe handling and containment of animal and zoonotic diseases."

Mr Joyce, who forced the relocation of the national pesticides authority from Canberra to his own electorate of New England, is facing a High Court test of his eligibility to sit in Parliament.

Labor and the crossbench have called for Mr Joyce and his deputy Fiona Nash to stand aside from their ministerial duties during the case, but the government maintains they will be found eligible to sit as MPs.

The government's wider decentralisation plans continue, with ministers required to tell cabinet last month why non-policy jobs in their portfolios shouldn't be relocated from Canberra, Sydney and Melbourne.

Business cases for a suite of forced relocations are expected by the end of the year.

The Northern Territory government is angry at the Coalition for moving Australian Electoral Commission jobs away from Darwin.

The AEC moved 14 of its 17 Darwin-based public servants to Queensland - part of trend that has seen the Northern Territory lose 15 per cent of its federal public service headcount since 2013, more than than any other state or territory.

Official figures show only 2220 Commonwealth public servants working in the Northern Territory.

Treasury said in April it had been unable to find an official to work in Darwin for three month placement, despite advertising the posting twice.