The union that represents 50,000 urban Canada Post workers says that its rotating 24-hour strikes will move to Victoria and Moncton, N.B., after the Crown corporation rejected the union's latest contract offer.

Sick leave benefits, starting wages and health and safety issues are key sticking points in the negotiations for the Canadian Union of Postal Workers.

Yannick Scott, a spokesperson for the union, said it wants Canada Post to address rising injury rates among its workers.

"Unfortunately there's no negotiation really on that specific point," he said from a picket line in Montreal, the latest city hit by the strikes.

The cause of rising injury rates is new sorting machines, the union says, which require the mail to be manually sequenced and leave mail carriers juggling several bundles at a time, "a bit like an octopus," Scott said.

The union announced the location of its next strikes, which will begin respectively at midnight local time, after Canada Post rejected its latest contract offer.

The Crown corporation said the union's offer failed to address Canada Post's shrinking mail volumes, rising competition and the creep of electronic mail.

According to spokesperson Jon Hamilton, the union's contract proposal would have added too much in labour costs and didn't "get anywhere near" what the corporation wants.

Canada Post later issued a statement proposing to scrap a plan to move towards more part-time jobs as a way of cutting costs, in the hopes that "CUPW would start to address the issues facing the postal system."

Meanwhile the latest rotating strike came to Montreal Monday. The union has also targeted Winnipeg and Hamilton since the strike deadline came and went without a deal late last week.

George Smith, a fellow at Queen's University's school of industrial relations, said that disruptions caused by the strikes will eventually undermine the negotiations.

"There's generally a level of tolerance for this kind of thing for a period of time if there's some hope that there is a settlement possible," Smith said.

"By not declaring war on each other, maybe a settlement is possible," he added. "There are diminishing returns to that strategy."

So far, Canada Post maintains the short-lived work stoppages have done little to disrupt mail service. But with workers now off the job for 24 hours in Montreal -- which is not only the largest city hit so far, but also a major postal hub in Quebec -- the entire province is expected to feel some effects.

In addition, Hamilton said that Canada Post needs to manage its costs during the rotating strikes and has taken steps like stopping overtime payments and refraining from calling in casual workers to fill in during absences.

The union said that Canada Post has also pulled temporary letter carriers from routes in a number of communities in the Prairies, including Edmonton, Calgary and Saskatoon.

"We feel this move is sort of putting the public at hostage as way of trying to get some sort of leverage with the union at the bargaining table," said Bev Ray, president of the union's Edmonton local.

Ray said that some temporary workers were told by Canada Post not to return for at least two weeks.

Businesses will also see their mail service increasingly disrupted as the rotating strikes hit larger urban centres.

"One problem will beget another problem further down the food chain and the system will become gummed up, I would imagine, in a week to 10 days," Dan Kelly, senior vice-president of the Canadian Federation of Independent Business, told The Canadian Press.

So far, Kelly said members have yet to complain, but said that could change if the rotating strikes hit Toronto, Calgary or Vancouver.

"We haven't had any calls from panicked members yet saying that they felt any impact of a strike. The one thing about Canada Post is that customers are well used to delays," he said.

Hamilton said the longer the rotating strikes go on the more widespread the disruptions will be.

In the meantime, the national president of the Canadian Union of Postal Workers is urging Canadians who value good jobs in their communities to tell Canada Post how they feel.

"Postal workers are staying out on strike to keep the pressure on negotiations," Denis Lemelin said in a statement released Sunday. "We will not accept the rollbacks that a profitable company is trying to force us to swallow."

Hamilton has repeatedly stressed that declining mail volume, increasing competition and a $3.2 billion pension deficit mean the crown corporation cannot continue with business as usual, the urban postal workers' union has balked at management demands for concessions on starting wages and sick-time benefits.

According to their latest proposal presented Friday, CUP-W 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 each of the next three years. The union said pension benefits for all employees including new hires must also be written into the collective agreement.

When postal workers last went on strike in the fall of 1997, they were legislated back to work after two weeks.

However long this strike lasts, both the union and Canada Post have promised Canadians who rely on the service for certain monthly federal and provincial payments that they can still expect 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.

Other cheques, including the third installment of Ontario's HST rebate, were post-dated and mailed out before the disruption began.

With a report from CTV Montreal's Caroline van Vlaardingen and files from The Canadian Press