The Australian Taxation Office is fighting a battle to force seven of its public servants to move offices from central Sydney to Parramatta in the city's west.

As federal government plans to force agencies out of Canberra gather pace, the Sydney dispute could be a test case for the Australian Public Service's ability to force its workers to relocate against their will.

The Fair Work Commission has been asked to rule on whether the ATO can force the seven bureaucrats to move from its Latitude East building in Sydney's CBD, to Paramatta 25 kilometres away.

More than 200 taxation staffers have already made the move from the city's Latitude East building and six have so-far been spared the trek after successfully pleading it would cause them undue hardship.

But the "Sydney seven", as they have been dubbed by their union, had their hardship pleas knocked back and were told to show up at the Parramatta office from Monday of this week.

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The ATO told Fairfax Media that workers had been given plenty of notice of the move and that consultation with their unions had been "extensive".

Last Friday, the Fair Work Commission gave the seven workers a stay of execution, ordering the ATO not to send them west until a conciliation hearing can be held this Thursday.

The move from Latitude East has been the source of simmering discontent for months.

About 50 workers from the ATO's service delivery branch were given their marching orders from the 20^th floor of the building, while the space they formerly occupied was converted into make new office suites for Commissioner of Taxation Chris Jordan, some of his top executives and their executive assistants.

The FWC hearing comes as forced relocations of bureaucrats from Canberra look likely, with Agriculture Minister Barnaby Joyce telling several agencies in his portfolio, employing about 600 public servants, to make plans to pack up and move to towns in regional Australia.

The Australian Service Union, which is representing the Sydney tax officials, says the case is test of the ability of public servants to uphold the terms of their departmental enterprise agreements.

"This Fair Work Commission hearing…is actually about employees being able to hold departmental secretaries to account when they do not comply with the provisions of their enterprise agreement," union official Jeff Lapidos said.

"This is why the Government is so intent [on] getting rid of so much of the content in these enterprise agreements.

"It means that departmental secretaries will be able to do whatever they want, and APS employees will have no practical ability to challenge poor decisions.

"One of the purposes of enterprise bargaining is to negotiate with departmental secretaries about how they will run their departments, so there is a proper balance between the interests of the secretary and the interests of employees," Mr Lapidos said.

An ATO spokeswoman said that Latitude East workers had known since May that they were expected to move.

"Staff were first advised of the move in May 2014 and we have undertaken considerable consultation with staff and unions," she said.

"Affected staff were individually advised of their requirement to relocate in July 2014.

"A small number of staff lodged hardship requests as provided for in the ATO enterprise agreement 2011.

"Hardship was found in some cases and we are working to assist these staff with options.

"Hardship was not found in other cases and those staff will be expected to move one month after being notified that no hardship was found."