brucem said:
Yes from what I have looked into, police, fire, or anything government related you need to be a Canadian citizen to apply for the post. All job postings for government related positions should tell you on the description exactly what criteria is required before you apply.
It doesn't seem to be only for citizens, see below:
(14.) Are newcomers to Canada eligible for a Security Screening and/or Security Clearance?
Newcomers to Canada are eligible for a security screening and/or security clearance. However, the individual must be a resident
of Canada for the past 5 years, and hold valid Permanent Resident status or Canadian Citizenship. Individuals who do not meet
these criteria may be granted a clearance, although limitation on access and certain types of information may occur.
source: http://ottawa.ca/cs/groups/content/@webottawa/documents/pdf/mdaw/mtkx/~edisp/cap201212.pdf