The OPI Muppets collection showed up on trademe and other online websites (beyond beauty, mj nailbank and candygirl) a few weeks ago. But wasn't officially released in New Zealand stores until the start of November.
This collection is now out in Farmers stores in New Zealand, and with that I presume other authorised stockists.
From the New Zealand suppliers website (Global Beauty):
Get ready to get your Muppet on this holiday season. As a tie-in to the forthcoming movie The Muppets, OPI is launching 12 limited-edition lacquers in time for Christmas. The collection includes six shimmery reds and neutrals, plus six glittery shades — perfect for holiday parties.
Lots of Love