A revitalisation of Australia's flood protection systems is required to reduce the impact of increasingly common severe floods, says University of NSW Professor of Civil and Environmental Engineering Ashish Sharma.

The engineering hydrologist warns that floods in NSW and Queensland earlier this year showcase Australia's limited protections.

Prof Sharma says climate change has made existing measures unequipped to handle the severe flooding seen in recent years.

"A lot has changed in the last 50 years. We have had significant changes in our climate, but the flood infrastructure and warning systems haven't caught up yet," he said.

"They have been put in place to expect little to no change – as it used to be in the previous 10, 20, or 30 years."

He says that Australia needs a major transformation of its flood warning and maintenance system to protect potential victims.

"A lot of the infrastructure needs to be redesigned, which will be costly, but the long-term benefits for the next generation are clear. If not, we're just going to be faced with the same problem over again.

"We can't control what comes down from the sky. But once it touches [the] ground, it's in our control – and floods happen because we didn't control it early enough," Prof Sharma said.

The NSW and Queensland floods earlier in the year are the costliest Australia has experienced, accounting for $4.3 billion of insured losses, the Insurance Council of Australia says.

Prof Sharma recommends changes across the board to reduce damage caused by flooding.

"The first line of defence is to improve the systems that feed the flood forecast modelling and issue warnings, so that we receive them much further in advance.

"Similarly, a lot of our infrastructure, such as dams and levees, needs to be redesigned because the floods they're supposed to be protecting us from are not the same as they were when they were built."

He also suggests that nature-based solutions such as green pavements, which absorb rainwater on a small scale, could play a role in the defence against flooding.

“Simple solutions such as green pavements and surfaces might not reduce the impact of a severe flooding event, like the one we had recently, but it can act as a buffer for the smaller flooding events that impact livelihoods.”

He explains that changes in the climate are causing floods to hit Australia in different ways, with higher temperatures causing drier soils.

"On one end we are seeing much more extreme floods and our old infrastructure, which has been designed on the assumption the floods would be the same size as they were many years ago, can't cope with it," he said.

"We are also seeing smaller floods from less extreme rainfalls because the storms are falling on drier soil.

"In a country that is facing natural disaster after natural disaster, year after year, it's clear we need well thought out solutions to mitigate the impact of the next disaster.

"We need the Government to back the research and legislate the solutions because ultimately it's the community who suffers unless better flood management practices are enforced."