Territory taxpayers paid more than $70 million this year to insure against public servants' workers compensation claims, up from $35 million in 2006-07.

The massive bill came despite the territory holding the cost of claims steady in the past three years and actually decreasing the number of employees absent from work and on compensation.

One agency, ACTION Buses, paid $8.8 million in workers' compensation premiums this year - far in excess of the $5.8 million the network paid to insure its buses, depots, machinery and passengers.

The federal government's workplace compensation insurer recorded a loss of $564 million for 2011-12, the first time Comcare has reported a loss.

The insurer did not respond to inquiries on Friday.

The hardest hit ACT agency this year was the Justice and Community Safety Directorate, which had its premiums rise 34 per cent to $11.6 million.

Education and Training will pay $12 million while the Health Directorate's bill will be more than $20 million.

The increases come despite an improvement in the number of claims in the ACT Public Service after the territory government established a centralised claims management unit and ordered it to emphasise getting injured staff back to work.

In 2010-11, 571 claims were recorded across the service.

The number fell to 529 in 2011-12 and just 173 in the first six months of 2012-13.

Claims expenses for the same periods were $41 million, $40 million and $22 million respectively.

Chief Minister Katy Gallagher said the back-to-work focus was working well but had not resulted in lower Comcare premiums.

''It wasn't only this year but it was the last two financial years where we've seen, not commensurate with our claims history, huge increases in the premium,'' she said.

''We've sought advice from Comcare, asked what is going on when we're putting more and more effort into reducing the number of injuries across the public service and we're seeing our premiums go up.

''It's a real problem because it's something we have to deal with in every budget, we get a notice asking for another $13 million, but I know what's involved in trying to find $13 million in saving across government.''

The Chief Minister said the self-insurance option might be considered in light of the growing premium bills.

''There has in previous [ACT] administrations been some reluctance to break away from the protection that's offered by Comcare but no other jurisdiction, as far as I can recall, goes in the Comcare scheme,'' Ms Gallagher said.

''They're all self-insurers and - to some extent - that puts additional discipline on the administration because they are the self-insurers and all of the risk lies with them and it's up to them to manage their claims.

"There is something attractive, I think, about looking at our insurance arrangement.''

Ms Gallagher said that she wanted to see the return-to-work focus continue on ACT claims.

''Across the insurance sector, you see that push to deal with the injury because that gives people a much better chance of returning to work in a full capacity and I don't think, in the past, we've been as focused on that,'' she said.

''In the past, that's how compensation schemes worked - you got injured, you got a lump sum, you went home.

''But the world's a different place now - people want to go back to work and they should come back to work and they should be returned to health.''