The Queensland opposition has condemned the government over "six sneaky taxes" contained in the business case for Cross River Rail, although the deputy premier rejects the claim that motorists will be slugged with levies.

A "car park levy" and a public transport "levy" on commuters were among the proposed taxes in the business case sent to the federal government, which also shows the project could cost $9.5 billion when ongoing running costs are included.

None of the proposed "secret taxes" being investigated have been adopted.
They show:

• a congestion tax, or car park levy, to raise $1.2 billion;
• land tax on nearby property owners to raise $1 billion;
• a "public transport infrastructure tax" paid by property owners to raise $2.6 billion;
• a "ticket surcharge" paid by public transport users raising $1.08 billion;
• a motor vehicle registration levy paid by motorists raising $1.22 billion; and
• and an estimate of $285 million raised by higher rates on nearby properties.

Although deputy premier Jackie Trad on Wednesday morning ruled out imposing an increase on vehicle registrations, the state opposition said the government was not being honest with Queenslanders about funding the giant project.

Acting Opposition Leader Deb Frecklington said "six new sneaky taxes" were "distressingly" being planned to
help fund the $5.4 billion project.

"These taxes include a land tax, a ticket tax, a congestion tax, the registration tax, and public transport infrastructure tax, and also an increase in rates," Ms Frecklington said.

The charges were outlined on pages 32-35 of an extract from the Cross River Rail business case document. Journalists were given a five-page summary on Monday and questions to Building Queensland on how "value capture" would be raised were "side-tracked" as being too early to be revealed.

However, Ms Trad said the vehicle registration levy option was only included in the business case at the behest of the Turnbull government, whose Smart Cities Plan requires all projects seeking federal funding to "assess value capture" options.

Ms Frecklington said Premier Annastacia Palaszczuk and Ms Trad "must explain how Cross River Rail is going to be funded".

The business case papers also raise questions about the ongoing costs of Cross River Rail, pointing out it would cost an extra 4.4 billion to run, manage and administer the project over its lifetime.

"The total project cost, excluding the net costs of providing the additional services, is $9.5 billion," the papers showed.

Shadow Treasurer Scott Emerson said the government was being "sneaky with Queenslanders" about how it would fund the project.

"None of those six secret taxes were mentioned when the government released its business case," Mr Emerson said.

"Now this business case was ticked off by cabinet before it was released.

"They knew about it, but they concealed it from Queenslanders.

"What Queenslanders need to know today is how much will this project cost and who is going to pay for it. And it appears the answer is Queenslanders."

Ms Frecklington and Mr Emerson said it was not appropriate to debate whether the "user pays" type charges being proposed were good ideas or not.

Ms Frecklington said Ms Palaszczuk promised to release the business case for every project worth over $50 million at the
previous state election.

"This is a project that is clearly over $50 million," she said.

Mr Emerson rejected the argument by Ms Trad that the government was "forced" by Prime Minister Malcolm Turnbull to include the extra schemes.

"If they were 'forced to include them, why didn't they come out 48 hours ago and say 'Look we got them in there, but we are ruling them out'," he said.

"They concealed them, by only releasing a five-page document."

The Queensland government promised $800 million towards funding the project on Monday, conditional on money from the federal government.

Both Prime Minister Malcolm Turnbull and Major Projects Minister Paul Fletcher have said the project was worth examining, but the business case needed to be seen.

Federal Opposition Leader Bill Shorten has promised a federal Labor government would contribute $800 million towards construction.