BEIJING (AFP) - Spying charges, calls for a probe into the origins of Covid-19, and now a body blow to Chinese Belt and Road ambitions Down Under - tensions between Australia and its biggest trade partner China are going from bad to worse.

Here is a look at the latest rupture in relations and how the long-running rumble started.

Goodbye Belt and Road Initiative

Australia on Wednesday (April 21) announced a revocation of the Victorian state government's deal to join China's sprawling Belt and Road Initiative, saying it did not meet national foreign policy priorities.

The decision comes after months of painful trade blows to Australian exports from Beijing, and routine exchanges of outrage over everything from espionage to the administration of Hong Kong.

By tearing up documents signed in 2018 and 2019 - a memorandum of understanding and a framework agreement - Foreign Minister Marise Payne risks seriously irking Beijing by taking aim at one of its big geostrategic priorities.

All eyes will be on China for a potential retaliation after Canberra's blow to President Xi Jinping's vast infrastructure plan to lasso much of the Asia-Pacific and beyond into China's orbit.

The tone was set early as China's embassy in Australia railed at the scrapping of the deal as "unreasonable and provocative".

Coronavirus origins

Australia last April joined the United States in calling for a thorough investigation into how the coronavirus transformed from a localised epidemic in central China into a pandemic - triggering outraged warnings from the Chinese ambassador to the country.

Chinese Ambassador to Australia Cheng Jingye said demands for a probe could lead to a consumer boycott of Australian wine or tourist trips, adding that the push for an independent inquest was "dangerous".

The call by Canberra that enraged China is seen in Beijing as a US-backed attempt to discredit it.

Trade hit

The rift has since left Australian exporters exposed, with China imposing a series of retaliatory bans on agricultural products such as beef, barley and timber.

Weeks after Mr Cheng warned of a consumer boycott, Beijing suspended imports from four major Australian beef suppliers.

Neither side openly linked the suspension to the call for an inquiry, citing technical issues instead.

But soon after, China announced anti-dumping tariffs on barley as well, and its latest measures take aim at Australian wine.

Detention and spying

Another area of contention involves high-profile Australian citizens detained by China: writer Yang Jun and journalist Cheng Lei.

China-born Mr Yang, who also goes by the pen name Yang Hengjun, was taken into custody in January last year and faces spying charges, which he denies.

Ms Payne has previously decried China's treatment of Mr Yang as "unacceptable".

Ms Cheng, an anchor for China's English-language state broadcaster, has been held since at least Aug 14. She was formally arrested in February this year, accused of "supplying state secrets overseas" - although Beijing has revealed few other details of the allegations against her.

Two Australian journalists were rushed out of China in September last year after the police sought to question them, while Beijing accuses Canberra of raiding its journalists' homes as it investigates an alleged covert influence campaign.

'Five Eyes' kickback

Australia is among Western allies - the so-called 'Five Eyes' - accusing China of violating its legally binding international commitments on Hong Kong after imposing a tough security law on the city.

The US, Britain, Australia, Canada and New Zealand have hit out at China for ousting pro-democracy lawmakers from Hong Kong's legislature and raised fears over the intentions of Chinese tech companies overseas.

But attempts to build a united front against China provoked a typically terse response from Beijing.

A foreign ministry spokesman warned: "No matter if they have five or ten eyes, if they dare to damage China's sovereignty, security and development interests, they should beware of being blinded."