Localism is a principle that is being spoken of more often. There are older terms like subsidiarity that have fallen out of use, in particular because people do not intuitively know what they mean. Localism has the word local in it and so is more straightforward of a concept.
Local Government NZ is supposed to be involved in promoting localism but they got sidetracked with their Three Waters campaign that would have removed local ownership of water infrastructure. Left-wing racial activism took precedence over campaigning for more delegated power over core local services.