Sydney's rain is becoming more torrential, particularly during summer, a trend researchers say will increase with further global warming and force engineers to design resilient structures that are able to limit the flood impacts.

A study of 69 rain gauges in the greater Sydney region from 1966 to 2012 found that the number of short but intense rainfall events increased, while longer-duration deluges decreased, according to research by the University of Adelaide published in Nature Climate Change on Wednesday.

"We see an increase in extremes in summer and relatively little change in other seasons," said Seth Westra, a senior lecturer in civil engineering at the university, and one of the authors of the report.

Dr Westra said extreme rainfall was increasing globally, with shorter events – such as those lasting less than an hour – "the most vulnerable to change".

"Flash flooding seems to be the thing that is most driven by atmospheric temperature," he said. "So, if the atmospheric temperature goes up, you can potentially get a lot more flash-flood-type events."

Scientists have long known the atmosphere can hold about 7 per cent more moisture for each degree of warming, although just when and where the rain falls depends on circulation and other factors.

The prospect that heavy rainfall events may become both more frequent and more intense has been one prompt to revise the Australian Rainfall and Runoff guidelines. First compiled in 1958, the national guidelines are now undergoing their first full revision in 28 years.

The new report will contain a chapter on climate change for the first time and include work from Dr Westra and his team. Jason Evans, an associate professor at the University of NSW's climate change centre, is preparing that chapter based on modelling out to 2050.

"The historical record doesn't necessarily give us a good picture of what we can expect in coming decades," he said.

"We do find that these [rainfall] extremes are increasing in the future, and we do find – in our model – that they increase by more than you'd expect, just based on the trend from the observations," Professor Evans said.

As brief rain events may become more extreme, engineers will have to reconsider how storm drains are designed, among other assets. Changes to longer-duration events, such as last week's east coast low-generated storms in NSW, would have implications for designs of dams, bridges and other larger assets.

"For the Sydney region, [longer-lasting storms] are expected to increase as well," Professor Evans said.

James Ball, an associate professor at the University of Technology Sydney's civil engineering school and chief editor of the new guidelines, said the revised report was scheduled to be finalised by the end of 2015, and would identify where flood risks were likely to increase or decrease around the nation.

It will also remove antiquated guidelines set up by different councils and even states.

For instance, the estimated flood exceedance measures used by engineers in Tweed Heads in NSW and Coolangatta in Queensland differ by a factor of two, depending on the location, even though both towns face approximately the same flood risk, Professor Ball said.

"Different states had different procedures," he said. "We're trying to remove those inconsistencies from the guidelines."