OTTAWA -- After spending hours studying a bill that would order an end to postal workers' rotating strikes, the Senate has voted to think things over for another day.

Senators adopted a motion Saturday evening to adjourn their discussion of the federal government's back-to-work bill until Monday afternoon.

The legislation, known as Bill C-89, was sent to the Senate early Saturday after the Liberals pushed it through the House of Commons in a special sitting that lasted until the wee hours of the morning.

Senators heard testimony from several witnesses, including Labour Minister Patty Hajdu, Public Services Minister Carla Qualtrough, Canada Post interim president Jessica McDonald and CUPW president Mike Palecek.

Sen. Peter Harder, the Government Representative in the Senate, said in a statement that he was pleased the bill had moved forward, “particularly given the holiday season.”

But he added that senators wanted more time to consider witness testimony, as well as whether the legislation complies with the charter.

“I am pleased work is well underway on this urgent legislation, which is very important to Canadians and Canadian businesses,” Harder said.

“I had hoped we could complete the debate this weekend, but I also understand that some senators might have wanted more time to study the bill in light of the testimony from ministers, Canada Post and the Canadian Union of Postal Workers before it moves to the final stage.”

If the upper chamber approves the bill, it will go into effect at noon eastern time the day after it receives royal assent.

The bill would appoint a mediator-arbitrator to help Canada Post and the union representing its workers come to an agreement. If mediation fails, the two sides would enter binding arbitration.

“It's a position I didn't want to be in, but our government has come to the point of last resort,” Hajdu told the Senate on Saturday as she urged senators to give Bill C-89 their collective nod of approval.

Members of the Canadian Union of Postal Workers have held rotating walkouts for a month, causing massive backlogs of unsorted mail and packages at postal depots.

Canada Post says it could take weeks - even stretching into 2019 - to clear the backlog that has built up, especially at major sorting centres in Toronto, Montreal and Vancouver.

CUPW's 50,000 members, in two groups, are demanding better pay for rural and suburban carriers, as well as greater job security and minimum guaranteed hours.

Supporters of the back-to-work legislation say it would help small businesses that rely on parcel delivery around the holidays.

Critics - including New Democrat MPs, some of whom walked out of the Commons in protest on Friday evening - say it infringes on postal workers' right to strike.