The southward shift of cyclones under climate change will force planners to demand stronger building standards as far south as Coffs Harbour on the NSW North Coast, Cairns climatologist Steve Turton says.

Storms such as the category 5 Cyclone Marcia, which crossed the central Queensland coast on Friday, "are going to become more common in the future along the eastern seaboard of Australia," Professor Turton from James Cook University told Fairfax Media.

Climate change is resulting in the expansion of the tropics at the rate of 150-300 kilometres every 30 years, bringing more regions in the path of potential cyclones, Professor Turton said. (See his essay in the 2014 State of the Tropics report.)

"The research is suggesting that, in a warmer world, we'll get more intense cyclones because there'll be more energy in the oceans and also the atmosphere," he said.

Climatologists say the atmosphere can hold about 7 per cent more moisture for every degree of warming, potentially adding clout to major storm events.

Last year, a study led by scientists at the US based National Oceanic and Atmospheric Administration, The Poleward Migration of the Location of Tropical Cyclone Maximum Intensity, argued that the areas where cyclones were reaching their most powerful were shifting towards the North and South Poles at the rate of 56 kilometres a decade.

"With their devastating winds and flooding, tropical cyclones can especially endanger coastal cities not adequately prepared for them," the NOAA said.

"Additionally, regions in the tropics that depend on cyclones' rainfall to help replenish water resources may be at risk for lower water availability as the storms migrate away from them."

Planning for storms

For north-eastern Australia, cyclones may become fewer in number but more intense when they form, Professor Turton said.

At present, buildings are required to meet high wind speeds only from Caboolture near Brisbane and northwards, leaving much of the Queensland capital uncovered by the tighter structural rules.

"I think they need to move that line down to Coffs Harbour this century [as part of] planning for a warmer world," Professor Turton said.

While south-east Queensland and northern NSW have been hit by big storms in the past - including the "Great Gold Coast Cyclone" of February 1954 - it is likely such events were "hybrids or intense east coast lows" rather than cyclones, he said.

"They didn't have the gales all the way around the centre and they didn't have the warm core" of cyclones, he said.

Kevin Walsh, a cyclone expert at the University of Melbourne agreed that Cyclone Marcia was an abnormal storm.

"It's pretty unusual for a category 5 cyclone to strike the coast of Queensland this far south," Associate Professor Walsh said.

Other big storms included a cyclone "very close to category 5" near Mackay in 1918 and Cyclone Dinah, a category 4 storm that stayed mostly offshore, Professor Walsh said.

Having more such storms tracking further south is "consistent with what would happen in a warmer world", he said.

The Bureau of Meteorology said the near-simultaneous landing of Cyclone Lam on the Northern Territory coast and Cyclone Marcia is the first recorded instance of twin severe cyclone events.

Professor David Karoly, a scientist at the University of Melbourne, said the prospect of fewer - but more intense - cyclones in the western Pacific basin under global warming is because of expected changes to atmospheric circulation.

The expansion of the tropics would likely result in a strengthening of the high-pressure belt over southern Australia, leading to reductions in rainfall, Professor Karoly said.

Some of that shift is already evident in south-western WA, where cool season rainfall in particular has dropped sharply in recent decades, according to the CSIRO and the Bureau of Meteorology. Similar reductions in rainfall are also becoming evident across the south-east.