Accounting is a field that is very popular with Canadian university students. Hence, there are more than enough Canadians with sufficient qualifications for the demand. As well, a new immigrant without extensive knowledge of the Canadian and US tax systems will be at a large disadvantage in seeking employment in this very competitive field.
You have to understand US taxes as well as a very large portion of Canadian companies either export to the USA or import from the USA. As well, many companies have operations in both countries and accountants in Canada have to be familiar with the USA.
If you come to Canada on PR, with an accounting degree outside of Canada or the USA, you would have to start at the level of a high school graduate in most cases.
Also, understand that we have entered a deep recession and many companies are going under which has released a lot of accountants to the job market.
Until the Canadian unemployment rate has fallen below 6% again, in a few years, will there be many opportunities in Canada for non-technical immigrants? Check the Canadian unemployment rate every once in a while