It appears a last-ditch offer by Canada Post to head off job action by its urban workers has had little effect.

A notice by the Canadian Union of Postal Workers this evening says rotating strikes are on, with the first one set for Winnipeg late tonight.

The union hopes its job action will encourage management to return to the bargaining table with a proposal that meets the needs of its members.

The union says it expects to meet senior post office management tomorrow.

The union says it's picking Winnipeg as the first rotating strike location because it was first city to feel the impact of Canada Post's modernization program.

Canada Post has said it needs to address labour costs.

It notes the letter-mail business has fallen by more than 17 per cent since 2006 due to digital communications.