I think a master's is a master's regardless of the time spent for the degree to be awarded. I completed my bachelor's in 3 years instead of 4 and my ECA states that it is equivalent to a Canadian 4 year bachelor's.
I think that as long as your diploma states that it is a master's degree, you should be fine, but the only way to be absolutely sure is to get an ECA report.
Hope this helps & good luck!