Former Immigration Department spokesman Sandi Logan said the decision was satisfying for him personally, though he was "decidedly uncomfortable" with some of the bureaucracy's attempts to crack down on staff views.

He also revealed that he, too, had concerns about offshore refugee detention, which one of his staff, Michaela Banerji, had criticised repeatedly using an anonymous Twitter account. She was later sacked for doing so, as well as for her criticisms of other policies and of Mr Logan.

The court ruled on Wednesday the decision to sack Ms Banerji was just, as she had breached her obligation as a public servant to demonstrate impartiality. It also found the freedom of political communication implied in the constitution was minimal and did not override the Public Service Act.

Mr Logan, now retired, is an outspoken and prolific user of social media, much like Ms Banerji. However, he had never previously commented publicly on the case.

"It has been many years since the Banerji matter has been on my radar," he wrote on Twitter.

"[I] never expected, when it was discovered a staffer in my ... team was operating a Twitter account under a pseudonym (and who regularly criticised the department's policies and related activities) that it would end up in the High Court.

"That said, the issue - for me, then (and now) - was always that, as public servants, we had an obligation to provide the government of the day fearless and honest advice/counsel, without allowing personal preferences/opinions/beliefs to hinder the process."

Mr Logan was a public servant for three decades, working in foreign affairs, policing and immigration, often in high-profile roles.

He told The Canberra Times on Thursday that, while "the right balance was met" in the court's decision, he was concerned by the Public Service Commission's latest social-media policy, which warned staff even against "liking" or sharing other people's posts.

"That, to me, is a keystroke too far."

Before her dismissal, Ms Banerji had worked as a public affairs officer in Mr Logan's team.

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She had accused Mr Logan of bullying her and had argued in an earlier, unsuccessful legal bid that the decision to discipline her over her Twitter comments was a retaliation against this complaint.

Mr Logan strongly defended how he had conducted himself, though he offered some sympathy to Ms Banerji, saying she had "clearly thought deeply about the issue".

"That this matter has finally been resolved in the High Court ... is satisfying, for me, because it brings to conclusion an important principle of public service impartiality and independence.

"That it has come at significant personal cost is, however, quite sad: we are all human beings with hearts and minds for whom hurt is never pleasant."

Earlier on Twitter, he wrote there were "many, many times" he was "decidedly uncomfortable" with government policies, naming uranium exports, the Iraq war, drug-crime policies and mandatory refugee detention, "especially reopening offshore processing in Nauru and Papua New Guinea".

"But as a professional communications executive committed to the APS, it was not for me to determine whether a media release or an interview would proceed because of my personal views. In fact, quite the contrary.

"A public servant uncomfortable with the government's policies on immigration who then, under a pseudonym, attacks the government publicly - both during her working day (as well as during her own time) - is not an unbiased employee whom the organisation can trust, let alone whose ongoing employment the agency could tolerate.

"I would not expect a communications branch member to stand on a street corner with a loud hailer criticising the government and its policies any more than I'd expect to see them posting tweets with similar criticisms."

He said that while many readers would not have known that Ms Banerji's Twitter alter ego, LaLegale, was run by a public servant, "many in fact did know, and this reflected very poorly on the team, the department and the wider public service".

"Having an opinion as a public servant and wanting to invoke 'free speech' so that opinion can be broadcast to all and sundry doesn't meet the logic test," Mr Logan wrote.

"Just because one believes strongly in a policy direction doesn't excuse a public servant from obligations to the APS code of conduct, as well as the department's own social-media policy. If one doesn't support the policy to the point a 100 per cent professional commitment is possible, get out of the department, or get out of the APS altogether."

Earlier on Wednesday, Ms Banerji apologised to her supporters.

"I'm very sorry that the court has cast this terrible shadow over our people. There's nowhere to go after this, there's nowhere to go."

She later posted on Twitter a picture of Picasso's Weeping woman, with a caption: "Weep for our world."