Christian Porter welcomed the court's decision against the former Immigration Department employee Michaela Banerji, saying the government would consider the result "in the near future".

"It is worth noting that the substance of the decision effectively supports the status quo regarding the expectations on Commonwealth public servants to not compromise the important independence of their departments or agencies," Mr Porter said.

Judges found on Wednesday the Australian Public Service's limits on free speech for staff were constitutional, clearing the way for punishments targeting bureaucrats who express political views.

Canberra employment lawyer John Wilson said the High Court did not find the federal bureaucracy's code of conduct stopped public servants making any public comment about anything political.

Justice Stephen Gageler had pointed out that the code required a "measure of restraint" from bureaucrats determined by the situation.

"But, in practice, that is hardly helpful," Mr Wilson said.

"The reality is that any public servant who makes public political comment is going to be at the mercy of the hierarchy within their agency and their assistants in HR as to whether what they've said has breached the code and, if so, whether, like Ms Banerji, they are going to be dismissed.

"The High Court was at pains to make it clear that it is not the court's job to determine whether a public servant's public comment has breached the code."

Australian Lawyers Alliance spokesman Greg Barns said the result showed Australians' free speech wasn't protected.

"This case shows that Australians lack fundamental protections such as freedom of speech. The lack of a national human rights charter means government can shut down dissent far too easily," he said.

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Former public service commissioner John Lloyd, who oversaw the release of strict social media guidelines for bureaucrats, said the court decision upheld laws governing public service employment.

"It shows the current arrangements are suitable and appropriate," he said.

Community and Public Sector Union national secretary Nadine Flood labelled the court decision disappointing and said it could affect almost two million Australians working across federal, state and local governments.

"People working in Commonwealth agencies should be allowed normal rights as citizens rather than facing Orwellian censorship because of where they work," she said.

"At the end of the day the government has a responsibility to protect freedom of speech. The Morrison government needs to demonstrate that it prioritises democratic rights, with a social media policy that reflects the real world."

The public service commission said it was giving careful consideration to the High Court's decision and would make further comment "in due course".