A labour disruption involving Canada Post will hit the Windsor-Essex area first.
As of Monday morning, the rotating strikes by Canada Post workers were underway at post offices in four Canadian cities.
"The union's rotating strike will therefore have a significant impact on our operations", the statement read.
Striking members of the Canadian Union of Postal Workers stand with placards in front of the Canada Post office in downtown Windsor on October 22, 2018.
The union says mail will still be delivered in those cities, but will be delayed.
"For us to reach any agreements, Canada Post has to talk about the changing nature of postal work and the issues that stem from the growth of parcels", said CUPW national president Mike Palecek in a statement.
Canada Post said that if there were to be a strike, its activities would continue with possible "minor delays". "Canada Post will make every effort to minimize the impact".
"The insane thing for Canada Post workers right now is they're fighting to keep making sure they have on-going relevance in the economy and yet the strike action is making sure more and more customers will bleed away from the corporation", says Dan Kelly of the Canadian Federation of Independent Business.
"We've done everything we could to try and reach an agreement and they're not just getting it into their heads that we're serious about the things we've been discussing", said Tony Rogers, president of the Nova Local of the Canadian Union of Postal Workers.
NSLC spokesperson Beverley Ware told NEWS 95.7's The Sheldon MacLeod Show Canada Post Expedited Parcel Service is used to ship online cannabis orders.
He said Canada Post has rural and urban units, and the issues for the two differ.
"There's nothing moving in Edmonton at all", she said.
"We always have back to work legislation in our tool box, (but) we're not anticipating using that in the near future".