OTTAWA, Nov. 26 (Xinhua) -- The Canadian Senate passed legislation Monday night ordering an end to five weeks of rotating strikes by Canadian postal workers.

Senators voted 53-25 in favor of the bill, with four abstentions, after two days of special sittings to debate the matter. The bill was rushed through the House of Commons last week.

Royal assent is expected soon, allowing the legislation to go into force at noon Tuesday.

The Canadian government said the passage of the bill is urgent due to the economic impact of continued mail disruptions during the busy holiday season.

The Canadian Union of Postal Workers maintains the legislation is unconstitutional and has vowed to challenge it in court.

The union wants better pay and job security, guaranteed hours for rural and suburban carriers, and equality with urban employees.

It also wants Canada Post to adopt rules that it says would cut down on workplace injuries, an issue the union has said is now at a "crisis" level.

Negotiations have been underway for nearly a year, but the dispute escalated when union members launched rotating strikes on Oct. 22 this year.

Those strikes have led to backlogs of mail and parcel deliveries at the corporation's main sorting plants in Vancouver, Toronto and Montreal.

Earlier Monday, picket lines were up in parts of the province of British Columbia, including Vancouver, Richmond and Surrey, and in parts of Ontario, including Hamilton, Ajax, North York, Pickering and London. Workers also walked off the job in Halifax and Dartmouth.

Canada Post said Monday that the backlog of mail and parcels is "severe" and expected to "worsen significantly" once online orders from Black Friday and Cyber Monday sales are processed.

It added that it is experiencing delivery delays across the country, which are expected to continue throughout the holiday season and into January.