Mining giant Rio Tinto Coal Australia has hit back at the Queensland government and its proposed hike on coal royalties with more job reductions.

Without detailing numbers, the coal mine unit of Rio Tinto announced it will slash the number of its manpower across all its coal mines in Queensland, ABC News said.

The latest action has a direct correlation to the Queensland Government's proposal to hike the existing coal royalties. Under the proposal, the rate on coal royalties will be increased to 12.5 per cent for prices between A$100 and A$150 per tonne ($100-$150/tonne). Anything higher will be taxed 15 per cent.

"The Queensland Government's decision last week to increase royalties is the latest example of the cost escalations affecting the coal industry," ABC News quoted an unidentified Rio spokesperson as saying.

"We are working to improve our competitiveness by actively seeking ways to reduce costs across our business, which unfortunately means some roles will no longer be required. These are not decisions we take lightly, jobs are being protected wherever possible and support is being provided for employees."

As early as August, when the state government first floated the coal rate hike idea, the Queensland Resources Council (QRC) had said mining companies will be forced to cut jobs in areas as a means to offset costs.

But Steve Smyth, district president of the Construction, Forestry, Mining and Energy Union (CFMEU), alleged that Rio Tinto has other motivations and is just using the coal tax hike as an excuse.

"The companies are using this as a bit of an excuse to trim the fat and make sure they maintain their bottom line and huge profits," Mr Smyth said.

"They'll use anyone - it could be the State Government."

Rio Tinto Coal Australia operates the Blair Athol, Hail Creek, Kestrel and Clermont mines in Queensland.

"I think a lot of these companies need to look at their own way they are managing, so there is a lot more than singly pointing out individual parties," Mr Smyth said.

"There's mean and mechanisms in place they can be doing to review their operations, it doesn't mean you've just got to cull and cut the workforce."