China has cancelled a major Canadian grain handler’s registration to export canola seeds to China in the latest flare-up of diplomatic and trade tensions between the two countries, CBC News reports.

A Chinese customs document dated 1 March said Richardson International’s registration had been cancelled, the news report said.

"Richardson has been directly targeted," company vice-president Jean-Marc Ruest said. "We think this is part of a larger Canada-China issue, and we hope it gets resolved expeditiously."

Ruest said the firm believed the issue was tied to a diplomatic dispute between the two countries when Canadian officials arrested Meng Wanzhou, vice-president of Chinese technology firm Huawei, at the request of US tax authorities as she was boarding a flight in Vancouver on 1 December. In late January the US Justice Department charged Huawei and Meng with conspiring to violate US sanctions on Iran. Meng is the daughter of Huawei's founder and has filed a civil claim against members of the Canada Border Services Agency, the Canadian police force and the federal government alleging “serious breaches of her constitutional rights.”

In addition, two Canadians have been detained since December and been accused of stealing state secrets from China.

Some industry experts believe the cancellation of Richardson’s permit is linked to the diplomatic issues.

Almost half of Canada’s US$3.72bn worth of canola exports went to China last year, amounting to some 5M tonnes, according to the Canadian Canola Growers Association.

CBC News said Richardson was among the largest individual shippers of the product in the world and China’s move would basically curb or shut down its canola exports.

"If Richardson can't buy and move it and send it to China, farmers are to be left with it here in Canada,” said association chief executive Rick White.

Newly-appointed Canadian Agriculture Minister Marie-Claude Bibeau said the government was “closely monitoring the situation and any potential impact on Canada's agricultural trading relationship with China”.