Coal is one of Australia's major exports, and China is a big customer, buying up nearly a third of it.

Beijing's already hit wine, seafood, timber and more all since Australia called for an international inquiry into the source of the coronavirus.

But hours after the news broke, Australian leader Scott Morrison issued a warning to China.

It's the $4 billion that goes into coal fired power generation in China.

Um, it really is a lose lose here.

The other countries have 50% higher emissions than Australian coal on as a result that that would be a bad outcome for the environment, Morrison said.

Any boycott of Australian coal would break international trade rules despite Chinese restrictions, experts say Australia's coal exports are expected to hold up well because of new buyers in South Korea, Japan and Vietnam.