Unfortuantely there isn't a simple answer. Sometimes yes, sometimes no. Speaking with other new immigrants who hold professional jobs in their own country, many have commented that while getting '
a' job is very, very important, many I talk to also recommend not rushing into it, if you can financial manage this, and focus on getting the
right job. Yes, it will likely take 3+ months to find something directly in your field, but to be very honest 3+ months is the typical timeline for anyone working in Canada. As an average, the 'process' just takes this long. This is the norm.
The other thing to consider if you initially get a blue collar job in Canada is that your resume will show professional jobs from your current country, then blue collar jobs in Canada and you're now trying to convince a new employer you want to go back to the other job -- you run the risk of having your resume look confusing.
Read the blog a friend keeps on his personal experience on immigration and job search, it may give you another perspective:
http://www.immigrationexpertise.com/2005/12/welcome.html