Today the Supreme Court of Canada issued the decision in the Saskatchewan Federation of Labour case on the right to strike---and yes, it is constitutionally protected.
The case can be found at the SCC website at http://scc-csc.lexum.com/scc-csc/scc-csc/en/item/14610/index.do.

My favourite quote from the majority 7 to 2 decision written by Madam Justice Abella is this:

[3] The conclusion that the right to strike is an essential part of a meaningful collective bargaining process in our system of labour relations is supported by history, by jurisprudence, and by Canada’s international obligations. As Otto Kahn-Freund and Bob Hepple recognized:

The power to withdraw their labour is for the workers what for management is its power to shut down production, to switch it to different purposes, to transfer it to different places. A legal system which suppresses that freedom to strike puts the workers at the mercy of their employers. This — in all its simplicity — is the essence of the matter.

(Laws Against Strikes (1972), at p. 8)

The right to strike is not merely derivative of collective bargaining, it is an indispensable component of that right. It seems to me to be the time to give this conclusion constitutional benediction. (my emphasis).

With this decision the 1987 Trilogy of labour cases decided just 5 years after the Charter has been completely overturned. The late former Chief Justice Dickson's eloquent dissent in that case has been vindicated.