The old economic rule of thumb was simple: when the US sneezed, Australia caught a cold.

It was an explanation of Australia's dependence, along with the rest of the developed world, on the American economy and its millions of well-paid consumers. But what happens when Australia's largest trading partner, China, shuts down key parts of its economy because of an outbreak of the coronavirus?

When China was hit by SARS in 2003, Australian iron ore exports to the country were worth just $1.7 billion. By 2018, they had reached $51.4 billion

In the past 24 hours companies as different as Toyota and Nintendo have warned of an economic fallout from the virus, which is forcing firms to shutter operations on mainland China with flow-on impacts to its suppliers.

Reserve Bank governor Philip Lowe, in evidence to a House of Representatives committee on Friday, noted there were already signs that local businesses would be affected as they struggled to replenish their inventories from Chinese warehouses and factory floors.