Talks between Canadian Pacific Railway and the union representing its 4,800 striking workers broke off Sunday, paving the way for the federal government to introduce back-to-work legislation when MPs return to Ottawa on Monday.

Teamsters Canada issued a news release early Sunday evening, saying a mediator that had been working to bring the two sides to a deal walked away from the talks at 2 p.m. Eastern time Sunday.

The statement said no other meeting between the Teamsters Canada Rail Conference and CP is planned.

"Unfortunately, the company negotiated in bad faith despite Minister Raitt's wishes," Doug Finnson, vice-president of TCRC, said in a statement. "Canadian Pacific was hiding behind the Federal Government since the very beginning of the process."

Labour Minister Lisa Raitt indicated last week that she hoped the two sides would come to an agreement on their own, but that the government was prepared to step in with back-to-work legislation should the two sides fail to reach a new deal.

While the union blamed CP for the stalled talks, the railway said Sunday it has been willing to consider extensions to the negotiating process and also to go to arbitration.

"The union chose to strike unnecessarily and put us into this turn of events," CP said in a statement. "The union constantly refused to consider the various options the company was agreeable to that could have minimized the strike and prevented the damage to our customers' businesses and employment levels."

The news came hours after Raitt expressed hope the two sides would come to a resolution, but indicated she was prepared to step in if the ongoing labour dispute appeared to threaten the economy.

Speaking with CTV's Question Period earlier Sunday, Raitt said the government was watching negotiations from an economic point of view.

"That is why we have put into play the 48-hour notice period and that is why we have said very clearly to the parties that, ‘If you don't find your own process, if you don't find your own deal, then you are going to get stuck with a parliamentary process,'" she said.

"We are cognizant of the effects on the economy and on their businesses and we are ready to act."

Some 4,800 unionized Canadian Pacific workers, including engineers, conductors and yardmen, went on strike early Wednesday after negotiators were unable to reach a contract agreement by the midnight deadline. Pensions and health spending accounts remain a key issue in negotiations.

The work stoppage brought freight service to a halt across the country and left shipments such as grain, fertilizer, coal, and auto parts undelivered.

For its part, the government has warned CP Rail and its striking workers that it could act soon with back-to-work legislation if a solution isn't reached soon.

Members of Parliament are on break until Monday and it's anticipated that the CP strike and looming legislation will be a hot-button issue when they return.

"What we want to communicate to the general public and to the sectors who are watching this very carefully is that we will get the procedural (issues) out of the way should we need to act in a quick manner," the minister said.

"But you still have to go through the process in parliament and things don't move fast there."

However, Raitt reiterated her desire and that of the government that the sides should reach an agreement without government intervention.

"It's a real team effort right now to gauge what is going on and make sure that we are balancing the two things; the national economy and the effects that a work stoppage has on it and indeed the need to collectively bargain at the table their own deal," Raitt said.

"They are a very private company and we want them to do their own deal or their own process."

The government has taken a tough stance in recent years on labour disruptions. Raitt stepped in on several occasions to prevent unionized pilots and airline workers from walking off the job, and intervened in a Canada Post strike as well.