OTTAWA (Reuters) - Canada's two main railway companies and the Teamsters union must do the hard work necessary to reach labor deals and avoid a full stoppage, federal Labour Minister Steve MacKinnon said on Monday.

In a post on the X social network, MacKinnon said Canadian National Railway ( CNI ) and Canadian Pacific Kansas City ( CP ) would shut down early on Aug 22 unless deals were reached.

MacKinnon said the effects of the talks would be borne by all Canadians.

"The parties must do the hard work necessary to reach agreements at the bargaining table and prevent a full work stoppage," he said.

Canada relies heavily on rail to ship grain, fertilizer and commodities and the country's main business lobby group estimates losses would hit C$1 billion ($733 million) a day.

The union says CN Rail and CPKC want to dilute safety provisions, a charge the companies deny.

Labor talks started early this year but progress has been slow, with both the union and the companies accusing each other of bad faith.

($1 = 1.3641 Canadian dollars)