The official took Comcare to the Administrative Appeals Tribunal earlier this month after the government agency refused her claim for workers' compensation.

She argued that an "arbitrary and unreasonable" deadline for a large piece of work had caused her to become "extremely distressed" and resulted in her suffering from anxiety.

The employee worked on procurement and contract support for areas of the Defence Department involved in tenders for work.

At the heart of the dispute was an email sent to the employee by her supervisor after she had voiced concerns about the size of a task she was asked to complete.

"With your other tasks, I think that the timeframes that you've been given are reasonable and that the tasks are achievable without you needing to work additional hours," the supervisor wrote.

"I had also requested that you provide a draft report for my initial review by 30 Jan 15 which I haven't yet received.

"If, in future, you have difficulty completing tasks, I would appreciate it if you can provide me with an update on your progress so that the workload can be managed appropriately and so I can ensure client requirements are met."

The employee did not see the email before she left work that day but became "extremely distressed" when she read it the next morning.

To complete the task she worked for more than nine hours straight without a lunch break, the tribunal was told.

In a discussion with another supervisor, the employee was also told that there were concerns about her ability to meet deadlines, the amount of time she spent in non-work related conversations and her personal use of the internet.

The employee saw these comments as a personal attack and took leave from work for the next four days.

"[She] says that the deadline...was arbitrary and unreasonable," the tribunal heard.

"She says that it failed to take account of the other tasks she had to complete, that the tasking was unclear and that she had not been given sufficient management support.

"Importantly, [she] says that the imposition of the deadline...caused her disease."

The federal government's Safety, Rehabilitation and Compensation Act defines a "disease" as any ailment that was significantly caused by a government worker's employment.

Comcare conceded that the employee's distress and anxiety could be substantially attributed to her work at the Defence Department.

However, it argued that the steps her supervisors had taken in flagging the deadline and discussing her performance issues had been reasonable.

At a hearing in Canberra earlier this month, the Administrative Appeals Tribunal affirmed Comcare's decision to deny the employee compensation.

"The email and the discussion were each causes of [the employee's] disease," the tribunal concluded.

"Each was reasonable administrative action taken in a reasonable manner in respect of her employment.

"Accordingly, her disease is excluded from the definition of 'injury'...Comcare is not liable to pay her compensation."