I was referring to ASX listed CFDs. My understanding is that they are bought and sold on the ASX with the ASX as the intermediary and there seems to be parties which act as the market maker with a spread of about 0.20 between the buy and sell on a stock like NAB. I have found that normally if I want to get in/out of a position quick, I'd have to sacrifice about 0.05-0.10. For this reason I am looking at a DMA provider that pretty much mirrors the underlying stock. Its not such a big deal I guess when you do only a few trades but I'm finding it gets a bit annoying when I trade quite a bit more.
http://www.asx.com.au/products/cfds.htm
I also was interested in stocks outside the ASX 200 ie short CRZ.