A planned protest will disrupt traffic in the downtown core on Sunday afternoon.
Police will be closing several downtown streets as the demonstrators, organized by the Canadian Union of Postal Workers, march to Parliament Hill.
Between 1 p.m. and 4 p.m. rolling street closures will occur between Dundonald Park and Elgin Street, police said in a media release.
Once protesters reach Parliament Hill, Wellington Street between Bank and Elgin streets, Elgin Street between Wellington and Queen streets and Metcalfe Street from Wellington to Queen streets will all be closed.
Police are advising people to avoid these areas.
In December, Canada Post announced that it would end door-to-door mail delivery, cut between 6,000 and 8,000 jobs and increase the price of stamps in order to reduce costs.
CUPW represents Canada Post workers as well as private workers.