Locked-out longshoremen are picketing the port. (Canadian Press)

Negotiators for the Maritime Employers Association and the union representing 850 locked-out longshoremen have reached a tentative deal to reopen the city's busy port Saturday morning.

On Friday morning, members of Canadian Union of Public Employees Local 375 will vote on the deal, but both sides are confident it will be accepted, allowing the port to reopen Saturday at 8 a.m. ET.

The two sides were in intensive talks all day Thursday in downtown Montreal with a federal mediator, and the key item on the agenda was lifting the lockout.

The agreement bringing stability to the port is to remain in effect until mid-October. The two sides have until then to negotiate a new collective agreement. Those talks resume Monday with a federal mediator present.

Business at the commercial dock came to an abrupt halt Monday after the Maritime Employers Association locked out some 850 longshoremen who are at odds with the employer over contract talks.

Some of the conditions of the agreement include an end to work slowdowns by union members, no more refusing overtime, and workers having to stay and work a full shift.

The employers group must bring back job security for all longshoremen and guaranteed work hours and revenue.

The port was closed to ships carrying goods into the city, forcing several companies to reroute their vessels to Nova Scotia and the United States.

Quebec's largest employers' group — le Conseil du patronat — has said it is "extremely preoccupied" by the labour dispute.

"It's normal to have contract negotiations. But it's important for the economy, and for Quebec companies, that the Port of Montreal get back to business as usual as quickly as possible. I'm talking days or hours," said Yves-Thomas Dorval, president of the Conseil du patronat.

Timely shipping is crucial for a number of companies, Dorval said, including Quebec's liquor stores.

Shipping containers that longshoremen would normally unload have been piling up at the port as workers picket the entrance. The Maritime Association obtained an injunction to restrict where pickets can stand.

They must now hold their line at least 10 metres from the entrance.

The lockout had been costing an estimated $800,000 a week, according to the employer.

Longshoremen have been working without a contract since December 2008. They are at odds with the association over paid on-call policy.

The Maritime Association wants to stop paying some workers to be on call for work, because they say it's too expensive. The union insists on maintaining the paid on-call policy, saying it's part of the job.

The port employs 5,400 people and generates an estimated $1.5 billion yearly for the Canadian economy. It is Canada's second-largest port, after Vancouver, and the eighth-busiest in North America.