A Canberra public servant sacked for expressing her views on asylum seeker policy, has won her case for compensation after the Administrative Appeals Tribunal of Australia found she was unlawfully dismissed.

In September 2013, Michaela Banerji was fired from the Federal Department of Immigration after it was revealed she had been using the anonymous Twitter name @LaLegale to criticise the then-government, the minister and department policies — particularly over the handling of refugees.

In one tweet Ms Banerji wrote:

"Think of the deaths we are responsible for in Iraq! Think of the refugees we have created by our invasion of Iraq!"

In another she said:

"When a nation state permits eighty-six percent of detainees to suffer mental health problems, it #fails. Understanding #itsnotwelfare"

Ms Banerji lodged a claim for workers compensation for post-traumatic stress disorder she said arose from her termination.

She brought proceedings before the Federal Circuit Court, the Federal Court and the High Court over several years.

Ms Banerji said her termination was unreasonable because it breached a constitutional right to freedom of political communication.

In a decision handed down by the Administrative Appeals Tribunal of Australia (AATA) this week, the tribunal overturned a decision by the Commonwealth insurer to deny her workers compensation — though the tribunal did not specify the amount of compensation Ms Banerji should receive.

During the tribunal's deliberations, it referred to the Australian Public Service (APS) guidelines that state:

"APS employees have the same right to freedom of expression as other members of the community, subject to legitimate public interests, such as the maintenance of an impartial and effective public service in which the community can have confidence."

The Tribunal ultimately found "the termination trespassed on the implied freedom of political communication, was thus unlawful, and so cannot constitute reasonable administrative action".

It likened Commonwealth efforts to restrict anonymous comments from public servants as resembling George Orwell's "thoughtcrime".

The AATA also found Ms Banerji had been careful to avoid tweeting in work hours.