Australia’s top grain exporter has been banned from sending barley to China after disputed claims pests were found in multiple shipments.

West Australian grain handler CBH vowed to fight the “extremely disappointing” decision, which appears to be the latest trade strike fuelled by diplomatic tensions.

Finance Minister Mathias Cormann said the federal government wanted to get to the bottom of the situation.

“We do respect the fact that China – like any other country would, like we would – has got quarantine inspection arrangements,” he told reporters in Canberra on Wednesday.

“We will be working with the company once we are aware of all the facts to make the appropriate representations.”

China’s customs department confirmed the decision on Tuesday, saying quarantine pests were found in CBH barley exports multiple times.

But the grain cooperative insists there is no evidence to support the claim.

“CBH is therefore extremely disappointed the suspension has been put in place and will continue to work with the Australian government to challenge the suspension,” the exporter said.

Australian farmers were already effectively blocked from exporting barley to China, which imposed tariffs of 80.5 per cent on the commodity in June.

Senator Cormann said CBH had a great track record, but declined to speculate if diplomatic issues had sparked the ban.

“The truth is, Australia’s grain products, Australia’s barley products, are highly regarded all around the world,” he said.

“If there is less opportunity to export high-quality Australian grain into China there will be more opportunity to export grain into other markets around the world.”

China has also launched anti-dumping investigations into Australian wine and suspended beef imports from five Queensland abattoirs.

Prime Minister Scott Morrison announced a constitutional power play last week, signalling the Commonwealth would gain veto power over state government agreements with foreign nations.

The beefed-up powers would allow the foreign minister to pulp Victoria’s belt and road initiative agreement with Beijing.

China’s deputy ambassador Wang Xining has revealed the depth of anger towards Australia over its push for an inquiry into the origins of coronavirus.

Grain traders have said while the CBH suspension will have limited impact, it signals a further deterioration in the Australia-China relationship.