China has imposed harsh taxes on Australian barley with separate tariffs of 73.6 per cent for dumping allegations and 6.9 per cent over supposed government subsidies.

Both claims have been emphatically denied by the government and farmers.

Diplomatic tensions between Canberra and Beijing have soared after Australia pushed for an inquiry into the origins of coronavirus.

More than 110 nations including China backed the inquiry at the World Health Assembly on Monday night.

Grain Producers Australia chairman Andrew Weidemann said the tariffs would have a huge impact on the industry.

"Most growers are completely gutted with the news," he told Sky News on Tuesday.

"It's really a bitter blow to the Australian economy as well."

He said farmers would lose $500 million in value out of the current crop, which most growers have just finished planting.

National Farmers' Federation chief executive Tony Mahar said China's claims were completely false.

"It is particularly devastating after the time that Australian farmers have had in the last number of years with droughts, floods and fires," he told ABC News Breakfast.

Australia is the biggest barley supplier to China, contributing more than half of its exports worth up to $2 billion a year.

Producers will be on the hunt for new export markets with India and Indonesia - which has recently signed a trade deal with Australia - considered prime options.

China claims the Murray-Darling Basin Plan and drought assistance amount to government subsidies.

Trade Minister Simon Birmingham is keeping the option of an appeal to the World Trade Organisation open.

"It's completely ridiculous to be listing things like the Murray-Darling Basin infrastructure upgrades as some sort of subsidy to barley exporters," he told reporters in Adelaide.

"The bulk of that barley comes out of Western Australia and South Australia and is firmly dry land for farming."

He said Australia had no interest in a trade war.

"We don't conduct our trade policy on a tit-for-tat basis," Senator Birmingham said.

"China we think, in this case, has made errors of both fact and rule in the application of those rules."

The global trade umpire could take up to three years to deliver a decision if Australia decides to pursue an appeal.

China's Ministry of Commerce announced the tariffs late on Monday after an 18-month investigation, with Australia-China relations taking a hit over a range of issues during that period.

"The investigating authority has ruled that there was dumping of imported barley from Australia and the domestic industry suffered substantial damage," the ministry said in a statement.

The tariffs come a week after China banned meat imports from four Australian abattoirs.

Beijing's ambassador in Canberra has also raised the prospect of consumer boycotts over the coronavirus inquiry.

Australian Associated Press