New Zealand milk token

I received this small (17 mm) milk token today:



The seller says it's a NZ milk token and indeed the "reverse" reads: WELLINGTON CITY CORPORATION with the seal/CoA of the city.

Now, is there anyone who knows how these were made? It looks like they used old tokens which they punched to a new size, with the whole + inscription conceived together, as evidenced by HA ○ LF.

A bump in the hope someone knows something about NZ milk tokens...