You are visa exempt, so if you can meet the following condition, you qualify to apply for a work permit on entry to Canada:
Eligibility to apply as you enter Canada
You can apply for a work permit as you enter Canada, but only if you meet the following requirements:
•you are temporary resident visa exempt and
• your job does not need a labour market opinion from HRSDC (some exceptions apply) or
•you hold a labour market opinion from HRSDC.
You either need an LMO, or you need a job that doesn't require one. Jobs that do NOT need an LMO are listed at this link below. If your skills qualify you under any of these categories, apply for a work permit on re-entry to Canada.
http://www.cic.gc.ca/english/work/apply-who-permit.asp