Questioned about it at a press conference in Queensland Trad said she thought some of the claims by both sides - Aurizon and the Queensland Resources Council - had been exaggerated.

She said the Queensland government was modelling what it believed the impact of the maintenance changes, which are expected to strip 20 million tonnes per annum from the Central Queensland Coal Network, would have on the state's budget.

That budget is due to be handed down on June 12.

"I will be making some statements in the state budget in relation to that [the royalty impact of Aurizon's changed maintenance practices]," Trad said.

She said she had been having constant conversations with both Aurizon and the QRC and was continuing to do so.

The issue has arisen because Aurizon insisted it had to remove the "flexibility" from its maintenance practices to meet the requirements of the Queensland Competition Authority's draft ruling on the CQCN.

It said the changes the draft ruling called for would be retrospective to July 1 2017, when the ruling was ratified.

Removing that flexibility, which will cause more track outages than its previous practices, will reduce the amount of coal that can be carried by the network.

The QCA released a consultation paper on Wednesday that rubbished some of Aurizon's claims.

The QRC estimated the change would cost the Queensland government $500 million a year in royalties.

QRC chief executive Ian Macfarlane said he hoped Trad was right and that the impact would not be so high.

However, he pointed out that Treasury was out in its previous royalties prediction by $1 billion.

"We hope this isn't going to be a major problem for Queensland," Macfarlane said.