An Australian barley cooperative is “extremely disappointed” after China suspended its exports, claiming pests had been found in its shipments multiple times.

CBH Grain Pty Ltd, which is based in Western Australia and is the nation’s top grans exporter, has confirmed it was notified by the Australian government it had been stopped from exporting barley to China, effective September 1.

The decision by China’s General Administration of Customs (GACC) was made – it said on its official WeChat account on Tuesday – after quarantine pests were found in its barley exports multiple times.

“In recent months, CBH was advised by the Australian government that GACC had notified them that several CBH barley cargoes, that had already been discharged in China, did not meet phytosanitary requirements,” the cooperative said in a statement to its 3,900 growers.

“CBH has not found any evidence to support these claims.

“The cargoes were all retested and it was confirmed that all cargoes met Australian government phytosanitary export requirements.

“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.”

CBH said the government was notified of China’s decision on Monday and it was advised on Tuesday.

The move comes after China levied hefty tariffs on Australian barley cargoes and launched probes into Australian wine imports, amid worsening relations between Beijing and Canberra.

China in May imposed anti-dumping and anti-subsidy duties totalling 80.5 per cent on Australian barley imports, effectively halting a billion-dollar trade.

China has also retracted CBH’s registration qualification for barley exports to China, according to the GACC notice.

Although Beijing’s move to suspend barley imports from CBH did not essentially affect trade, it shows that the relation between the two countries is not easing, traders in China told Reuters.

“Impact of removing it (CBH) is limited as we couldn’t bring in Australian barley already (due to the tariffs,),” a China-based grains trader said.

“But it is a signal, showing that Australian firms will be in an unfavourable situation. People will be rather cautious when buying Australian goods now,” said the trader, who declined to be named as he was not authorised to talk to the media.