I don't exactly know the answer to your question, though I am also interested in finding some. I did figure out that it is sold by Velcro in the US (/North America) as Velcro Ultra-mate. (at least I think this is the right stuff.) Most of it seems to have an adhesive backing, but I think the links below might be the right stuff... though information is a bit scanty.
Amazon: (black in color, unfortunately
http://www.amazon.com/Product-VELCRO-USA-Inc-Water-Resient/dp/B005FCOYDW/ref=sr_1_4?ie=UTF8&qid=1316710453&sr=8-4
Ebay: (this is more than you could ever use, unless you resell it --- and it is in large sheets of yellow & black, and costs 99 USD)
http://www.ebay.com/itm/7-x-150YD-Velcro-ULTRA-MATE-HK22-7-Perforated-771pcs-/120779085905?pt=LH_DefaultDomain_0&hash=item1c1efe9851
I've also seen this product sold in places like Home Depot, though unfortunately, it is double sided (hook on one side, loop on the other). It is sold as a strap for organizing extension cords, etc.
http://www.createforless.com/VELCRO+brand+One+Wrap+Strap+3/4x4+Black/pid35004.aspx
I'm sure it must be available with a bit more searching! A fabric / notions retailer would do well to get their hands on the right stuff and re-sell.
BTW, do you know if it is used on diapers in Oz? Does it hold up to many uses & many washes?
Let us know if you are successful in your search, and how it works out in your diaper-making!
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