Canberra COMCAR driver Lynette Prater suffered a long-term shoulder injury as a result of lugging the eight bags almost three years ago, but workers' compensation authority Comcare refused to pay.

The part-time driver took her fight to the Administrative Appeals Tribunal and won the right to have her medical expenses and lost wages covered.

But Comcare then took the case to the Federal Court, alleging the tribunal had made several technical legal errors when it decided in Ms Prater's favour.

Comcare's lawyers also tried to cast doubt on the driver's credibility after she did not report the injury straight away but only sought treatment after the pain failed to abate.

But the insurer's appeal was dismissed by Justice Annabelle Bennett,who also awarded costs to Ms Prater.

Comcare must now pay Ms Prater's claim or appeal to the full bench of the Federal Court.

Mr Smith had said he had no memory of the incident, but he or his staff would usually offer to help carry their bags and heavy document cases.

The then 49-year-old COMCAR driver picked the minister up from Canberra's RAAF Fairbairn airfield late on November 20, 2011.

Ms Prater's official incident report said: "Mr Smith came out and had two small silver cases with him. I then went to pick up the cases. They were extremely heavy and I could only manage to take one up to the car. He said he had a few more cases.

"Mr Smith put something else in the boot then went and sat in the car, whilst I loaded the remaining cases in the boot."

When they arrived at Parliament House, Ms Prater was left to unload the cases from the vehicle.

"Arriving at the basement, Mr Smith went and got a trolley for him to take the cases inside and left me to take them out of the boot unassisted.

"Left arm a bit tingly. I put this down to being a sore muscle."

She later told Fairfax Media she accepted the task when it became clear she was expected to lift the minister's bags on her own.

"I just shrugged my shoulders and thought, 'Oh well, I'm going to have to do it'," she said.

The driver said she hoped the severe pain in her shoulder would go away, but when she was diagnosed with a muscle tendon sprain, she wanted workers' compensation.

In denying her initial compensation claim, Comcare cited the delay between Ms Prater sustaining the injury and lodging the claim.

But after hearing the evidence, the Administrative Appeals Tribunal found there was no other likely cause for Ms Prater's injuries and the driver had done the right thing by waiting to see if her pain would settle down before seeking help.

In her decision, handed down on Friday, Justice Bennett backed the tribunal's decision.