Canberra woman Danielle Small was left unconscious when she was thrown from a horse while training with a ceremonial AFP mounted unit in March 2009, later diagnosed with a serious back injury, sprains and bone bruising.

The ongoing effect of the injury caused her to fall down stairs at home in 2011, but a review of medical advice has put her eligibility in doubt for $549,000 she has already received.

Ms Small has launched action in the Administrative Appeals Tribunal, with the case to consider if her injuries continue to be work-related.

Lawyers say attempts to recover settled compensation pay outs are part of an aggressive new agenda by the federal government, but Comcare says any debt could be waived or repaid in instalments.

"It was a training day in March 2009, and we went out doing a bit of show jumping to familiarise the horses," Ms Small said.

"I went over a relatively small jump and the horse threw me off. As someone who has been riding my whole life, I got back on and went around again.

"I was thrown off again, this time I was knocked unconscious and the horse, from what I was told, trampled on me."

The 30-year-old had occasional pain and needed ongoing treatment, but she continued to work towards her goal of becoming a sworn police officer.

"I got home from a training session in 2011 and walked up my stairs there was this loud click in my lower back.

"It caused me to lose control of my legs and I fell down the stairs, causing further aggravation to the injury."

Facing significant financial difficulties, Ms Small eventually received compensation and back pay, but in February last year she was informed the decision had been overturned.

The news caused her to faint and hit her head on a door.

"It is absolutely debilitating. Comcare has made me feel stalked, intimidated, bullied, harassed.

"The idea of being able to buy a house or something like that with this hanging over your head... it's completely impossible.

"Financially I am still struggling. I can't always afford to go to the GP. Sometimes I will have run out of pain medication and I have to go without and make do."

Maurice Blackburn lawyer Georgia Plunkett-Scott said the firm believed Comcare was revisiting settled cases to improve its financial position.

"Comcare have obtained a new report, they've relied on that report even though it was an outlier and they've effectively said we've changed our minds, we got it wrong, now we want huge amounts of money back and we're going to pursue you legally for that.

"Our firm has been doing this work for nearly 100 years and in our experience this is unprecedented.

"A review of the matters within our national practice indicates an approximately 50 per cent increase in recovery cases over the past six months, compared to what we have seen at any one time in previous years.

"If the decision does not go our way, soon after a civil claim can be pursued by Comcare against Ms Small for the debt."

A Comcare spokesman said the insurer's approach to debt recovery was "neither new nor aggressive" and debts were only pursued when appropriate.

"In this instance, the case is still before the AAT and Comcare is not pursuing a debt.

"Should a debt be created following the outcome of the AAT proceedings, the applicant is entitled to apply to have the debt waived or enter into a structured repayment arrangement that allows for individual circumstances.

"We will always consider alternatives in such cases," he said.

Earlier this month, Administrative Appeals Tribunal deputy president Gary Humphries labelled efforts to recoup payments to an ACT government employee as "unconscionable" and said Comcare had used unethical tactics.

Comcare rejected the comments and said the recipient would not be forced to repay money.