Thousands of heritage buildings across the country could be at risk of collapse if and when a populated centre is struck by an earthquake, experts warn.

Dr Mark Leonard from Geoscience Australia said on average, at least one magnitude-5 or above earthquake is expected to strike somewhere in Australia's earthquake zones every year but it is hard to predict exactly where.

"As we know from the Newcastle earthquake, you can get damaging earthquakes, in virtually all Australian cities, except Darwin and Hobart are probably the two cities we least expect to have earthquakes," Dr Leonard told 7.30.

"But in all other cities we expect there to be Newcastle-type earthquakes at some point."

Thirteen people were killed in the magnitude-5.6 Newcastle quake in 1989 and the damage bill reached about $4 billion, prompting a dramatic overhaul of construction requirements.

A recently released seismic hazard map by Geoscience Australia has identified the most vulnerable areas on the continent.

It is based on information from about 38,000 recorded tremors and reveals nearly all capital cities were built on the most active areas.

Dr Leonard said while there were no major fault-lines, large earthquakes were still possible because the continental plate was under strain, setting off quakes from time to time.

"Australia is very unusual in that we're moving north due to tectonic motion but we're being squeezed from east to west and we're slowly shrinking," he said.

"We think Perth is slowly getting closer to Sydney, by about a millimetre a year, and that is being accommodated by earthquakes rupturing on faults."

Geoscience Australia has identified the most vulnerable areas on the continent. ( GeoScience Australia )

Buildings constructed before the '90s at risk

But Geoscience Australia researcher Mark Edwards said many buildings constructed before the 1990s were not built to withstand large earthquakes.

"Older unreinforced masonry buildings are particularly vulnerable; also poorly detailed reinforced concrete buildings of medium rise, they are also vulnerable," he said.

"But if buildings are designed to current standards, generally they would travel quite well through a magnitude-5 earthquake."

Mr Edwards said heritage buildings were the most at risk of causing injury of death.

"We have older legacy buildings that contribute disproportionately to the risk and we know from the Building Codes Board that the rate of renewal is only about 2 per cent a year," he said.

"In New Zealand, they are assessing these buildings, they're retro-fitting them and they found retro-fit levels should be about two-thirds of current design level to be effective but here in Australia we have a knowledge gap in a way in understanding just what level of retro-fit would be appropriate here.

"So there's work underway presently with the Bushfire and Natural Hazards Cooperative Research Centre in developing cost effective strategies for our most vulnerable buildings."

Australia is considered moderately active on a global scale; for example it is more seismically active than northern Europe but less than Japan, western United States and New Zealand.