For a couple weeks now I have been reading Keith Draper's book
'Trout Flies in New Zealand'. A very interesting book, which was published
in 1971. One very important point is that there are no Matuka flies named
in it. There is a Matuku fly, with the original recipe using the Australasian
bittern feathers and the modern (1971) version using hen pheasant flank
feathers. There are quite a few patterns using various feathers in what is
known to us as the Matuka style, but no mention of the word Matuka.
It looks like the the word was coined outwith N. Z., possibly in Australia.

I bought Derek Quilliam's book 'A Complete Guide to N. Z. Trout Flies' 2000 from AbeBooks and now await its arrival.
I hope to dress some flies and will post the results.
( Complete with recipes of course.)