More than 800 postal workers will strike in communities across the country Wednesday night, as the 24-hour localized job action shifts away from Calgary and Edmonton.

Meanwhile, Canada Post announced it will reduce staffing levels at sorting plants and cut back on mail deliveries in urban areas.

"This is all as a result of the 50 per cent drop we've seen in our volumes in the last five days due to the union's rotating strike activity," said Canada Post spokesman John Hamilton.

Both sides will meet Thursday, when the union said it will give its response to Canada Post's service cuts.

Speaking to CTV's Power Play on Wednesday, Labour Minister Lisa Raitt said the federal government has been working to help the parties reach a deal, but little progress -- if any -- has been made.

"I'm very concerned. It's affecting seniors, it's affecting businesses, and it will affect the overall viability of Canada Post," she said.

The last time postal workers walked off the job in Canada was 1997. It lasted two weeks until the government forced them back to work through legislation.

Raitt said she has no plans to do the same.

"A deal they reach themselves is the best deal," she said.

The Canadian Union of Postal Workers said its members will strike at the following locations after 11:30 p.m. ET:

  • Labrador City, N.L.
  • Acadie-Bathurst, N.B.
  • Summerside, P.E.I.
  • Ste. Therese, Que.
  • Jerome, Que.
  • Thunder Bay, Ont.
  • Hearst, Ont.
  • Brantford, Ont.
  • St. Thomas, Ont.
  • Flin Flon, Man.
  • Yellowknife, N.W.T.
  • Whitehouse, Yukon
  • Vernon, B.C.

Earlier this week strike actions took place in Moncton, N.B. and Victoria. The week prior Winnipeg, Hamilton and Montreal were hit.

The strike in Calgary and Edmonton, which involves 4,000 unionized workers, is expected to last for 24 hours, wrapping up Wednesday night around 9 p.m.

John Bail of the CUPW executive said the two cities were chosen for strike action because both suffer from a chronic shortage of Canada Post workers.

The Canadian Press cited Bail as saying there are "a lot" of unresolved issues between the union and management and there was "very little activity" yesterday at the negotiating table.

However, Bail said the union sees no need yet for a nation-wide strike and will continue with the rotating strikes for now.

Meanwhile on Tuesday, Jon Hamilton, a spokesperson for Canada Post, said the company is waiting for the union to respond to its latest offer.

"This generous offer is what's on the table, while the union continues their disruptive strike activities across the country," Hamilton said.

Union officials have said that there is a disagreement about pensions, staffing and the short-term disability plan in the next contract.

The CUPW wants Canada Post to convert more temporary positions to permanent jobs, and more part-time positions to full-time jobs.

A statement posted on the Canada Post website on Monday indicated that the latest CUPW proposals "remain too expensive and fail to address the challenges facing the postal system."

Canada Post says that mail volumes are in decline, the post office faces greater competition and the public is increasingly using electronic services in lieu of traditional mail.

The employer's latest offer, according to a news release issued on Tuesday, offers a starting wage of $19 per hour for new hires, topping out at $26 per hour, up to six weeks vacation time and a defined benefit pension by age 60.

That package, Canada Post said, is superior to anything being offered by the company's private sector competitors.

Canada Post said on Tuesday that mail volume has dropped by as much as 50 per cent since the strike began, marking a serious financial blow to the corporation.