Postal workers in Hamilton will be following their Winnipeg co-workers onto the picket line this weekend, as their union tries to increase pressure on continuing negotiations with Canada Post.

Union of Postal Workers president Denis Lemelin said workers in Hamilton will walk off the job late Friday, as part of the ongoing action across the country.

"Tonight, starting at 11:45 Eastern time, our co-workers in Hamilton will walk out on strike for the next 48 hours," Lemelin said.

"We will continue to negotiate, but we must add pressure on Canada Post," he said, suggesting the public phone the Crown corporation with the message: "You have to sit down and negotiate a good collective agreement."

The union is hoping to keep Canada Post from instituting changes it says would weaken health and safety measures.

For its part, Canada Post has said it needs to reduce labour costs because its lettermail business has dropped of by more than 17 per cent since 2006, as customers increasingly move to digital communications.

Approximately 150 people took to the picket lines in Winnipeg at 10:59 p.m. CT Thursday night.

CUP-W said Winnipeg was chosen to begin a promised series of rotating strikes because workers there were the first affected by the introduction of new mail processing machines at the heart of grievances with Canada Post's "modernization" program.

"It does often catch a bit more attention for us with the corporation just because they don't know what city it's coming to next, so there is no preparation for them," CUP-W Winnipeg local vice-president Lisa Peterson said.

Canada Post spokesperson Jon Hamilton said he hoped the Winnipeg walkout would mark both the beginning and conclusion of the job action.

"We're hoping this is the end of it," Hamilton said, suggesting the 24-hour strike "is completely unnecessary and it's a huge disruption to our customers."

One group anxious to see a speedy resolution to the strike is charities that rely on mailed donations.

Ann Barnard Bell, development officer with Yonge Street Mission in Toronto, told CTV News Channel that she is concerned about having to cut services.

The mission, which provides services including keeping kids out of gang activity, takes in 70 per cent of their donations through the mail.

"Our hope is that people who have traditionally given to us through the mail would go online and make an online donation or telephone their donation in."

Latest offer

In its latest offer tabled, Canada Post said it would be willing to put a controversial short-term disability program on hold, pending a neutral review.

But Lemelin cited safety concerns as a primary point of conflict.

"We will continue to strike ... the goal is still the same, it is achieving a good collective agreement," Lemelin said in Ottawa Friday.

In addition to losing business to online services, Canada Post says it's also bearing a $3.2-billion pension deficit, leaving the corporation no choice but to address labour costs.

"The postal service is under threat from the Internet and we do need to change for the future," Hamilton said, referring to the CPC's proposal of a defined benefit pension plan for both new and existing employees as well as a lower starting wage than the $23 new hires are paid now.

But in her view, Winnipeg letter carrier Michelle Fidler doesn't think that argument stands up to scrutiny.

"The corporation isn't telling people that they have made up for that loss volume in regular mail ... they've made up for it by soliciting more and more addressed and unaddressed ad-mail contracts," Fidler told The Canadian Press.

"I have 453 residential calls that I go to everyday. It measures out at eight miles a day. And I go to almost every house every day. I rarely skip a house. There are volumes there," she said.

The union's approximately 48,000 members have been in a legal strike position since May, when its members voted 95 per cent in favour of striking.

In its proposal, the union is seeking a four-year contract with a guaranteed wage increase of 3.3 per cent in the first year, followed by 2.75 per cent increases in the next two years.

When postal workers last went on strike in the fall of 1997, their two-week job action ended with federal back-to-work legislation.

However long the strike lasts, both the union and Canada Post have promised Canadians who rely on the mail for certain monthly federal and provincial payments that they'll still get their cheques.

On one day each month, Canada Post employees have volunteered to leave the picket lines to deliver Canada Pension Plan, Old Age Security and Child Benefits cheques.

With files from The Canadian Press