Thanks rupeshhari for your feedback.
I suppose its no different to sending a covering letter - it's not a requirement at the initial stage, but from what I've been reading, plenty of people do it anyway. There's no evidence to support the claim that it would have a neg effect on the application.
In my case, I am applying as a Chef and in the NOC category it covers a whole range of kitchen positions. As I have worked my way up through all of them, they are all relevant to the category and I suppose it also helps support my claim to more than 4+ years experience (17 in my case)