Postal service is expected to resume Tuesday after a marathon session in Parliament finally pushed through back-to-work legislation over the weekend.

Bill C-6, aimed at ending a Canada Post lockout, received royal assent Sunday evening. The last official day of Parliament before its summer break was June 23, but the opposition extended debate on the bill into the weekend. The Senate examined the bill Sunday prior to assent.

The bill comes into effect tonight at 8:30 p.m., 24 hours after final approval. The union has advised its workers to be ready to report to work.

The union is upset about the act, noting the wage increases for union workers laid out in the bill are lower than Canada Post's latest offer. A government-appointed arbitrator will select a final offer from either Canada Post or CUPW, but the wage provisions in the bill are binding. The new collective bargaining agreement selected by the arbitrator would be in effect until Jan. 31, 2015.

The union noted Sunday, "We need to send a strong message to Canada Post that the lockout was wrong, and that their reliance on legislation is shameful."

Jacques Coté, COO of Canada Post, also issued a statement to employees Sunday. "I understand this has been a very difficult and stressful time for you and your families," he noted.

Coté said Canada Post will begin to "progressively re-instate service" starting Monday. "However, in order to ensure an orderly start-up, we will resume our operations in stages, starting with mail processing and transportation, followed by retail and collection and delivery."

Urban delivery will resume June 28, according to the Crown corporation. Mail pickup for commercial customers begins the same day.