After I submit an offer of employment, do I have to wait for it to be approved before the temporary worker can apply for a work permit?

No, you do not have to wait. When you successfully submit the offer of employment through the Employer Portal, you will be given an offer of employment number. You will find this number in the employment queue in your portal account. You need to give this number to the temporary worker. The worker must include the offer of employment number in their work permit application.

The worker can apply for a work permit as soon as they receive the offer of employment number from you.