Mail and parcels are continuing to pile up at Canada Post depots across the country as continued job action threatens to put the holiday mailing season into a tailspin.

Officials say that there is a massive backlog of items waiting to be delivered and with unions blocking any overtime worked by employees, clearing the backlog has become much more difficult.

“As of this morning at our Gateway parcel processing plant in Toronto, we surpassed 260 trailers of parcels and packets waiting to be unloaded. Union picket lines came down in this city late this morning, but the resulting backlog is beyond any previous record of backlogged trailers, with more expected today after two days of missed customer pickups due to the strike,” Canada Post said in a statement released on Friday.

People in Calgary say they haven’t been seeing too much of a delay so far under the rotating strikes, but the concern is there.

“I ship through Canada Post quite a bit and I do quite a bit of business in the United States and the U.K.,” said Karen Pickles, owner of Stresscase, a company that sells gift boxes.

She says that making her customers aware about the issue with Canada Post is really the best thing to do at this point.

“I just make sure that my customers are aware and that their expectations are to wait a little longer for their packages to arrive.”

Pickles says she hasn’t heard about any problems from her customers yet but hopes the strike will end soon.

“Hopefully this strike isn’t going to interrupt our business because it would kill us.”

Hundreds of trailers are currently backlogged at the major parcel centres in Toronto and Vancouver and without the ability to clear them out, it’s unlikely that the service will be able to manage the glut of the Black Friday and Cyber Monday deliveries.

As a result, Canada Post has announced that it would no longer accept any incoming items at any international posts, including the U.S. Postal Service.

“The backlogs are also extending to international mail and parcels entering the country. As a result, we have been forced to advise international posts, including the United States Postal Service, that we are unable to accept incoming items until further notice. We are working to help clear backlogs at Seattle airport and LAX,” the company said in the statement.

The labour action is now in its fourth week and has affected every Canada Post location and mailing address in the country.

Canada Post has offered workers a deal to ensure that service returns to normal in a reasonable amount of time. That deal has an expiration date of November 17 at 11:59 p.m. EST.

(With files from Chris Epp and CTVNews.ca)