The Queensland government has been accused of hiding tax hikes on the big end of town to prop up its budget.
Treasurer Cameron Dick has foreshadowed coal mining royalties will rise in 2022/23 after what he says is a decade-long freeze.
"Obviously that resource belongs to the people of Queensland and now we're looking at what that might look like in the future," he told reporters on Wednesday.
Mr Dick said the changes were still being worked out ahead of his June 21 budget.
In December, he forecast coal royalties of $4.6 billion for 2021/22, up from $2 billion predicted in last year's budget.
Queensland Resources Council chief executive Ian Macfarlane said surging coal prices will end up lifting royalties to $6 billion in this financial year.
He said the industry had been trying to speak with Mr Dick about royalty changes since February, but the treasurer put off talks until last week.
Mr Macfarlane said the industry doesn't have any details about the plans.
"So we're literally punching at smoke," he told reporters.
The resources council boss warned raising royalties without consultation or warning could make Queensland a sovereign risk for investors.
"They said they weren't going to put up taxes," Mr Macfarlane said.
"The outcome of that is if you're an investor and you've got to choose between Queensland, South America or somewhere else, you say 'Well, Queensland is just too hard'."
News of a coal royalty hike comes days after the government said it would increase taxes on bets taken by wagering firms from 15 per cent to 20 per cent.
Mr Dick said 80 per cent of that revenue will go to race regulator Racing Queensland, with the remainder to flow into government coffers.
He didn't care about what multinational wagering companies thought about the tax increase.
"I make decisions that are in the best interest of Queenslanders," the treasurer said.
Mr Dick has also taken control of bond holdings from the Residential Tenancies Authority, allowing the government reap interest earnings from rental bonds.
Liberal National Party leader David Crisafulli said the government had more revenue coming in than ever before, but it was still looking to "take money out of the pockets of Queenslanders".
Mr Dick last week foreshadowed a deficit of less than $1.7 billion in 2022/23, down from the $2.4 billion deficit forecast just six month ago.
On Thursday, Australian Medical Association Queensland called for $2 billion in funding for 1500 hospital beds to ease capacity pressures, and boost mental health and palliative care services.
The Chamber of Commerce and Industry Queensland called for the budget to cut red-tape and offer support to businesses to decarbonise.