A strike is underway at Canada Post.

Some 55,000 postal workers represented by the Canadian Union of Postal Workers went on a nationwide strike at midnight.

The Union says after a year of bargaining with little progress, postal workers made the difficult decision to strike.

In a release, CUPW said Canada Post had the opportunity to prevent the strike but has “refused to negotiate real solutions to the issues postal workers face every day.”

Canada Post’s operations will shut down during the strike, affecting millions of Canadians and businesses across the country ahead of the holidays.

Mail and parcels will not be processed or delivered for the duration of the strike, and some post offices will be closed.

Service guarantees will also be impacted for items already in the postal network. No new items will be accepted until the national disruption is over.

After the strike, all mail and parcels in the postal network will be delivered as quickly as possible on a first-in, first-out basis once operations resume.

However, Canada Post says a national strike of any length will impact service to Canadians well after the strike activity ends.