And another Commonwealth bureaucrat, who says she was bullied during an anti-bullying workshop, has lost her bid for more compensation for the post traumatic stress disorder she says she suffered from the incident.

Kay Brown, who said she "pulled a muscle in my bum" as she fell from a desk at a South Australian Centrelink office while hanging decorations there on December 5, 2000, has lost her legal action for compensation for permanent impairment.

The public servant suffered persistent backaches and buttock pain in the wake of the accident but Federal workplace insurer Comcare accepted liability only for aggravation of a pre-existing injury because Ms Brown had back pain before the festive mishap at Centrelink's Murray Bridge office.

She was compensated by Comcare for the injury in 2011 but in 2012 claimed the fall had left her "permanently impaired".

When Comcare refused to pay, Ms Brown took her case to the Administrative Appeals Tribunal which heard medical evidence that she had a prolapsed disc in her spine and the fall from the desk may have been a factor in the injury.

But expert witnesses also said Ms Brown had a degenerative disease in her spine before the fall.

Tribunal Deputy President Katherine Bean found Ms Brown might have suffered her long-term back problems with or without the fall.

"Even if the fall had not occurred, Ms Brown would have suffered the degree of permanent impairment which she currently suffers," deputy president Katherine Bean said.

"It follows that that permanent impairment, which would have eventuated regardless ... is not compensable."

In the other case, a former public servant who said a "respect and diversity workshop" held by her employer four years ago left her with post traumatic stress disorder, has had a legal setback in her attempt to get more compensation.

Karen Hutchinson, who has been off work and receiving workers' compensation since 2011, has gone to the Federal Court in Perth to have her payments backdated for a year.

But her court case fell at the first hurdle.

Ms Hutchinson said she suffered a mental breakdown after being subjected to a "death threat" in the workshop on workplace bullying on March 5, 2010.

The former claims manager for federal workplace insurer Comcare said during a role-playing exercise simulating threats in the workplace, her boss whispered to her: "I'm going to f---ing kill you."

Comcare agreed to pay out the claim, but only from 2011 when she was first diagnosed, instead of the date of the "death threat" incident, March 5, 2010.

Ms Hutchinson took her case to have the payments backdated to the Administrative Appeals Tribunal, which ruled against her, and then to the Federal Court.

But Justice Neil McKerracher has refused to grant the former public servant more time for her case to be heard, with the judge finding that Ms Hutchinson had failed to find an error in law in the AAT's decision against her.

"The underlying problem is that there is no error of law identified," Justice McKerracher wrote in his judgement.

"Rather, Ms Hutchinson is dissatisfied with the conclusion reached by the Tribunal."

The appeal was dismissed with Ms Hutchinson ordered to pay her former employer's legal costs.