Barley farmers are bracing for a huge plunge in income after China imposed crippling tariffs on Australian imports and are urging the federal government to appeal to the World Trade Organization.

The Asian superpower announced an 80 per cent, five-year tariff on Monday, sending shockwaves through the industry given it is Australia’s largest export market.

The slug comprises a 73.6 per cent tax over allegations Australia “dumped” barley too cheaply into China, hurting domestic production, and a 6.9 per cent tariff on supposed Australian government subsidies.

WAFarmers president Rhys Turton said it was “an absolute joke” as subsidies to Australian growers were the lowest in the world, while the dumping claims had not been substantiated.

The Commonwealth had stressed the trade dispute was a separate issue to Australia joining international calls for answers from China about the origin of COVID-19, but those in the industry could “join the dots at the moment”, Mr Turton said.

“I think we’ve been a bit of a soft target,” he told AAP on Tuesday.

WA Agriculture and Food Minister Alannah MacTiernan said it appeared barley growers had been caught up in a much larger issue.

“We have every confidence that Australian barley is neither being dumped nor subsidised,” she said.

Ms MacTiernan said China’s decision could slash WA farm incomes by up to $200 million this year through reduced barley values and lower wheat prices, as more farmers turned to wheat crops.

“I think it will be significantly more than that,” Mr Turton said

He said China’s brewers and maltsters preferred Australian barley, but would turn to supplies from Europe and North America.

Growers in Western Australia, which is the nation’s largest barley producing state, were devastated, Mr Turton said. Some had already planted for this season.

“It’s a blow. The industry would certainly support the government in its efforts on appeal.”