Brisbane City Council says a called-for levee around the CBD would not have prevented the disastrous 2011 floods.
Design and consultancy firm Arcadis released its City Resiliency: More than just a disaster report on Tuesday.
It said Brisbane risked falling further behind other domestic and global cities unless it addressed three key issues, one of which was major flooding and stormwater surges.
The report called for a levee to be built around the CBD, from Boundary Street at Spring Hill to the Eagle Street dining precinct.
But a council spokesman said it would not have prevented the 2011 floods because it was caused by river water coming up through the drainage system, not from overflowing banks.
"BCC has since installed 44 individual backflow prevention devices across 12 stormwater systems at a cost of $15 million to reduce the likelihood of similar flooding in the future," he said in a statement on Tuesday.
"Backflow devices are attached to the end of stormwater systems or in large chambers constructed over the pipes upstream from the outlet, allowing water to exit the pipes but not re-enter."
Arcadis' southeast Queensland city executive Louisa Carter said Brisbane could not become an economic capital until it confronted "some simple truths".
"One of the biggest international spotlights Brisbane had recently was when its CBD flooded," she said in a statement.
"We will never attract the scale of investment that Sydney and Melbourne enjoy until businesses can be confident that the city is resilient."
The report also called on governments to look at Brisbane's embedded energy network system and how to start to create a leading smart city.
The state government has been contacted for comment.