The benefits of Cross River Rail have been "significantly overstated" and its $5.4 billion cost is likely to exceed its benefits, Infrastructure Australia says.

But Deputy Premier and Transport Minister Jackie Trad has slammed the assessment as flawed. 

Infrastructure Australia's latest advice keeps Cross River Rail as a high priority initiative, recognising the issue of rail capacity through the Brisbane CBD.

But IA did not include the current proposal for Cross River Rail on the infrastructure priority list.

It said IA would welcome the opportunity to consider a revised business case which addressed its concerns with benefit estimation and clarified the estimated timeframe for the emerging capacity problem.

"A revised business case should also quantify potential benefits from land use change and urban renewal expected to result form the proposed project, and potential benefits from better integration of Brisbane's rail and bus networks," the IA project evaluation summary reads.

Infrastructure Australia also managed to invent a new suburb called "Hill Gate" in a map on the front page of its project evaluation summary - presumably it is an amalgamation of Hill End, West End and Highgate Hill. 

In a briefing note, Cross River Rail Delivery Authority head Graeme Newton said IA's summary contained "inherently flawed advice, with 23 instances of unsubstantiated opinions, assertions or errors".

Mr Newton recommended potentially withdrawing the CRR business case from the IA review process. 

The Queensland government has committed to fund the project without federal government assistance if necessary.

More to come...