In a statement, Mihychuk says the agreements were reached “voluntarily” but provides no other details about the deals themselves.
The negotiations were extended twice since the weekend, when a deadline expired on a 72-hour job action notice issued last Thursday by the Canadian Union of Postal Workers.
The two sides were in talks nearly around the clock at the request of a special mediator appointed Friday by Mihychuk.
Canada Post described the tentative agreements as short-term. It said they are for two years and that four-year contracts were typically negotiated in the past.
“The agreements will avert a work disruption, bringing much-needed certainty in the postal system for our employees and customers,” said Canada Post in a statement. “Canadians can now use the postal system with confidence.”
The tentative agreements, however, still must be ratified by the members.
The Canadian Union of Postal Workers is Canada Post's largest union, representing more than 50,000 postal workers.
The tentative settlement came the same day that calls for direct federal government action in the matter had grown louder.
Prime Minister Justin Trudeau had again been asked to get personally involved, this time by a group of prominent women from across the country who called on the prime minister to direct the Crown corporation to live up to its legal obligations on pay equity.
A day earlier, small businesses that rely on web-based sales were encouraged to write Trudeau and demand legislation to break the impasse.
The issue of differences in paycheques for rural mail carriers _ most of whom are women _ and urban letter carriers has been at the forefront of contract talks between Canada Post and its biggest union.
An open letter sent to the prime minister Tuesday called on Trudeau to keep his promise to support equal pay for work of equal value.
“We are asking you to use your influence to ensure that rural and suburban mail carriers achieve pay equity with (urban) letter carriers.”
It is not known what the tentative deals contain in regards to the pay equity issue.
Trudeau is in China this week for a formal state visit.
Tuesday's letter was signed by 200 women primarily from English-speaking Canada, including actress Sarah Polley, author Naomi Klein and social activists Maude Barlow and Judy Rebick.
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Labour Minister MaryAnn Mihychuk says Canada Post and the Canadian Union of Postal Workers have reached tentative agreements, averting the prospect of a labour dispute that has loomed over the talks for months.