Despite popular perception to the contrary, an uninhibited right of expression – such as that found in the first amendment to the United States constitution – is not bestowed on Australian citizens by our equivalent founding document. As Judge Warwick Neville explained in a 2013 case involving a tweeting public servant, "the unbridled right championed by [the applicant] ... does not exist".

All Australians do, however, enjoy a degree of protection from government interference with political communication under an implied freedom derived from the representative system of government required by the constitution. Subject to an exception for reasonably appropriate and adapted intrusions, the government cannot silence its citizens.

In the age of social media, the "right" of public servants to criticise government policy or otherwise make remarks in conflict with the official "line" is increasingly relevant, as indeed it is for private sector employees. In 2014, AGL Energy's Loy Yang facility was in the spotlight of the Fair Work Commission for requiring employees to "not make public comment about any matter, or participate in political activities, which can be attributed to [their] employment with AGL". The Construction, Forestry, Mining and Energy Union's challenge to this direction ultimately failed, but not before a consideration of the "fine line between activity and comment as a private citizen and what may be seen by AGL as attributable to employment".

While there is much case law regarding an employer's ability to regulate the out-of-hours conduct of an employee, this issue takes on particular significance in the Australian Public Service because of the special position held by its staff.

The Australian polity has come a long way since 1902 public service regulations expressly forbade government officials from publicly discussing or promoting political movements. While such "draconian" restrictions would now be considered problematic, the broad, underlying rationale – "from national security and cabinet secrecy through privacy protection, to the maintenance of an impartial and effective public service in which the public can have confidence" – remains applicable today.

Those comments come from Justice Paul Finn, who was faced with the dilemma of balancing free speech and legitimate government interests in the 2003 Federal Court case of Bennett v President, Human Rights and Equal Opportunity Commission. Peter Bennett was a Customs employee and president of the Customs Officers Association. He was directed not to make media comment that disclosed information of which he had official knowledge, and was charged with a breach of the Public Service Act after giving a radio interview.

In invalidating the regulation on which the direction was based – which, along with its predecessors, had been "a threatening presence for Commonwealth public servants for over 100 years" – Finn held that the restriction on speech was not reasonably appropriate or adapted to the legitimate ends asserted by the government. A judicial reminder was thereby made of the "rights and freedoms that ought to be enjoyed by Commonwealth public employees notwithstanding their public employment".

Since Bennett, though, several events appear to have threatened the delicate balance struck by Finn. In 2012, the Australian Public Service Commission issued a circular on public comment by APS employees, noting that the right to freedom of expression enjoyed by staff was "subject to legitimate public interests", while, in 2014, Department of the Prime Minister and Cabinet employees were allegedly urged to "dob in colleagues posting political criticism ... on social media".

In the 2013 case referred to above, of Banerji v Bowles, an Immigration Department employee, Michaela Banerji, lost an injunction application after being referred to a code of conduct investigation in light of anonymous tweets she had made criticising immigration policy. After reiterating that Australia has no first amendment equivalent, Neville indicated that Banerji's tweets – made while she was "(a) employed by the department, (b) under a contract of employment, (c) formally constrained by the APS code of conduct, and (d) subject to departmental social media guidelines" – were not constitutionally protected.

To return to McIntyre: the SBS journalist was not, of course, an APS employee and slightly different considerations therefore apply in his case. But regardless of individual views on the sentiment he espoused – which to some was probably highly offensive – his dismissal raises a worrying spectre. As Human Rights Commission President Gillian Triggs wrote in the incident's aftermath, a "practical, chilling outcome" of Australia's limited free speech protections "is that we must suffer the consequences if that speech is also a breach of an employment contract".

While McIntyre's court proceedings may shed some light on this issue in a quasi-private sector context, a judicial pronouncement on the extent of the government's ability to restrain their employees from making public comment does not appear imminent. Until such time, encroachments on Bennett may continue.

"Public servants," Finn observed at the time, "cannot be 'silent members of society' ". APS decision-makers would be wise to heed this warning, lest political communication in this country becomes a "dialogue of the deaf".

John Wilson is the managing legal director at Bradley Allen Love Lawyers and an accredited specialist in industrial relations and employment law. john.wilson@bradleyallenlove.com.au