Hi fellow Kiwi!
First of all, I know acrylic is cheap n' cheerful but spare a thought for real wool- it can be worth the extra cost, has a lil bit of extra spring/give (makes crocheting easier) and feels so much nicer in your hands... anyway...
Where abouts in NZ are you? There are a couple of major companies in NZ (like Knit World, they have branches all over) and a number of companies online (such as Skienz, who organized all those knitted penguin jackets after the Rena spill). If you're in Auckland, like I am, here's a few places I would recommend:
- Knit World in Henderson: they have a huge range, knowledgable staff. Look out for John Q Creative and Charity brand (these are wool, but are cheap and come in a range of solid colours)
- Masco Wool, downtown Westfield: they usually have a few bargain bins at the front of the store, you can get 50g balls for a few bucks.
- The Warehouse: seems to stock acrylic yarns exclusively
- Looksharp Mart, by the Whitcoulls downtown: cheap, acrylic wool and a range of other notions. This place is an absolute warren and is definitely worth a visit
- Mishi Yarns, Onehunga: if/when you want something a bit more luxurious
10 ply wool doesn't tend to be a common weight for acrylic yarn in my experience but you may be able to achieve the desired gauge/ weight by crocheting with two strands of yarn.
I hope this helps