Where might I buy bike parts in bulk in Sydney or online?

I'm looking to get good quality bike parts at a cheaper price per unit than I would get at my local bike shop. I'm thinking of using them for personal use on my bike and my family's bikes, as well as for refurbishing and reselling bikes. I had hoped I could buy them directly from Shimano, but when I went onto the site I could look at products but as far as I could tell there was no way to actually buy them. I did see a few archived posts with some good links, but I thought it wouldn't hurt to ask again Anyway, any assistance would be appreciated :)