The range of New Zealand shows available isn't huge and includes only a couple of releases from before the 1990s. With rise of streaming services it would be a brave person indeed to predict many more shows will get a physical format release unless the market for local tv shows skews nostalgic older folk who love a murder mystery but can't get the hang of streaming services, though I haven't found a whole lot of older shows on local ondemand services either.
I've partnered with Kiwi online store Might Ape; if they stock a Kiwi Tv show I try and link to it there, and if you follow one of my links to their site and end up buying something I get a micropayment to help pay the webhosting bills for this site.