The snag comes as Canada has shipped more pork this year to China, where the domestic pig herd has been ravaged by African swine fever. The two countries are also locked in a diplomatic and trade dispute that has resulted in China blocking imports of Canadian canola from two companies.

Reuters reports that so far, China has not imposed restrictions on Canadian pork, and the Canadian Food Inspection Agency (CFIA) is not aware of either the Chinese government or its importers causing new delays, a spokeswoman for the agency said in an email.

The current shipping problem involves different language and formats used between older and current export certificate forms provided by the CFIA, she said.

The shipping glitch is a "paperwork problem," but Canada continues to ship pork as normal to China, said Gary Stordy, spokesman for the Canadian Pork Council, which represents the country's hog farmers.

The Canadian government is now pressing Canadian exporters to seek replacement export certificates "on an urgent basis," as both current shipments and some others in transit to China are affected, the CFIA spokeswoman said. She did not estimate the volume of pork affected.

On Sunday, the CFIA issued a notice urging exporters to use the most recent version of the form.

China was Canada's largest pork export market by volume during the first two months of 2019, buying 59,000 tonnes from Canada, or 23 percent more than it did a year earlier, according to Statistics Canada.

The uptick reflects China's increased dependence on imported pork due to the spread since last August of African swine fever. The disease could mean the deaths of up to 200 million pigs in the world's largest producer and consumer of pork, according to Rabobank.