A Canberra public servant has been forced to cover the cost of her augmentation surgery after failing to convince a tribunal her breast size caused workplace injuries.

Australian Taxation Office worker Roseanne Howes' case was first heard by the Administrative Appeals Tribunal (AAT) in January 2015 after Comcare refused to cover the cost of the surgery.

Ms Howes underwent a $19,956 breast reduction in 2009, after already receiving a payout for a separate workplace injury caused by long hours hunched over her desk at work.

Ms Howes claimed painkillers prescribed to her following the initial injury caused her weight to balloon from 65 to 104 kilograms, leaving her with F-cup size breasts.

Tribunal member Dr Marella Denovan initially told Ms Howes in 2015 she should have first tried exercising or a diet program like Jenny Craig or Weight Watchers before opting for the expensive augmentation.

Late last year Ms Howes took her case to the Federal Court where a judge ordered it be reheard.

Last Friday the AAT rejected the public servant's appeal for the second time.

AAT senior member James Popple said while Comcare accepted her injuries it was not responsible for covering the cost of her breast reduction.

"I have found that the surgery could not have affected the symptoms (of her) compensable injuries," Dr Popple said.