On June 1, 2014, if you hold a study permit and a work permit under the Off-Campus Work Permit Program, you may continue to work off campus under your existing Off-Campus Work Permit.
On June 1, 2014, if you hold a study permit and you have applied for but not yet received your Off-Campus Work Permit, you should wait for your work permit application to be processed and begin working off campus once you have received your Off-Campus Work Permit.
On June 1, 2014, if you hold a study permit but you have not yet applied for an Off-Campus Work Permit, you are authorized to work off campus without a work permit as long as you meet the eligibility requirements for working off campus.
If you apply for a study permit on or after June 1, 2014, the conditions relating to your eligibility to work off-campus will be written on your study permit.
In all scenarios, you must continue to meet the conditions of your study permit in order to remain eligible for off-campus work. If you are studying English or French as a second language (ESL/FSL), or participating in general interest or preparatory courses, you will not be eligible to work during your studies, unless you become eligible to apply for a work permit with a positive Labour Market Opinion from Employment and Social Development Canada.
It is your responsibility and your employer’s responsibility to ensure that you are eligible to work off campus without a work permit before you begin working. If you begin working off campus without meeting the eligibility requirements, you may be subject to enforcement action under the Immigration and Refugee Protection Regulations.
http://www.cic.gc.ca/english/study/study-changes.asp