The government finally pushed through legislation Saturday night to get postal workers back to work next week, following a lengthy filibuster from Opposition MPs that stalled a vote for nearly three days.

The back-to-work legislation, derided by the NDP and union groups as anti-labour, passed in the House of Commons just after 8 p.m. after a 58-hour session in Parliament.

The government stood behind the back-to-work bill, saying that small business and other organizations like charities were being choked out by the mail dispute.

After the vote, Prime Minister Stephen Harper walked out of the chamber with Labour Minister Lisa Raitt to announce the legislation had passed.

"We know what side the public was on and I think today members of Parliament on the other side finally started to get that message," he said.

Harper also condemned the three days of round-the-clock debates leading up to the vote, calling them a "completely unnecessary delay."

This week's political maneuvering not only stalled the House vote, but it forced MPs to sleep in their offices, take shifts in Parliament and delay the beginning of their summer vacation.

But the NDP has said the legislation is a dangerous precedent that eliminates collective bargaining.

NDP Leader Jack Layton didn't talk to the media following the vote, but his deputy, Quebec MP Thomas Mulcair, said the filibuster was "a shot across the bow of the Conservatives."

"It's an indication of what's to come for other public service workers who are unionized," said Mulcair. "But it's also a signal from the Conservatives to all employers -- in a union setting or otherwise -- that it's an open bar. They can start going after the acquired rights of their workers."

The strike began on June 3 with a series of rotating strikes that shut down mail facilities in cities across the country.

However, when the strike moved to Montreal and Toronto, Canada Post locked out its employees on June 14 and said that the rotating action was costing millions of dollars.

Talks between the postal workers union and Canada Post management collapsed on Wednesday, following an impasse about entry-level wages, benefits and the age of retirement.

The two sides again met on Saturday morning, but no agreement was reached. By the evening, the NDP finally relented and the bill passed.

The legislation will now go to the Senate.

Though the opposition eventually conceded, they did manage to initiate the longest filibuster related to back-to-work legislation in Canadian history, according to CTV's Richard Madan.

Union leaders have said that they don't plan to defy the legislation, given the huge penalties for doing so. Union members can be fined $1,000 each day, while the union can be fined $100,000.

"We've looked at what the penalties would be and I don't think any of our members or officers of the organization could withstand the financial penalty," said union representative George Kuehnbaum.

"Will there be bitterness going back? Certainly not towards members of the public, but our members will certainly be bitter toward management," he said.

Though mail service is expected to resume soon, Canada Post still must grapple with the reality of a rapidly changing industry.

The crown corporation has seen a 17 per cent drop in mail volume over the past five years, with the cause mostly attributed to online services and private competitors.

Declining mail volumes, less reliance on the post office and the emergence of electronic banking and social media has taken a substantial amount of business away from Canada Post, according to one business professor.

Ian Lee, a professor at the Sprott School of Business in Ottawa, said he believes the drawn out labour dispute only did further harm to Canada Post's weakening reputation,

Lee also chided the NDP's decision to delay back-to-work legislation, predicting that the measures would only render the corporation more irrelevant.

With new advancements like email and new technologies like e-readers and digital music, the need to have a service dedicated to delivering mail and packages is on the decline, he said.

With files from the Canadian Press