Canada Post is warning customers of a possible 72-hour strike notice to be issued between now and Aug. 25.

A statement released by the crown corporation on Aug. 17 says talks between Canada Post and the Canadian Union of Postal Workers (CUPW) have come to an "impasse" following nine months of negotiations.

CUPW's 60 day strike mandate will expire on Aug. 25, the union is looking to extend the strike mandate, something which is not likely to happen.

"They are looking for the Corporation’s support to extend the strike mandate on behalf of employees," the statement reads, "Which is unprecedented and would be completely inappropriate. It would only provide further uncertainty for employees and Canadians."

If a strike begins mail service will be halted, any letters or parcels in the system will not move until service resumes.

Canada Pension Plan, Working Income Tax Benefit, Old Age Security, Canada Child Benefit cheques will still be delivered.