There is no language "test" for New Zealand citizenship. There is a requirement to
be able to hold a basic conversation in English
which is assessed at the interview (by holding that basic conversation in English), or by demonstrating by documentation that you can. The statutory requirement is
that the applicant has sufficient knowledge of the English language
No part of the law refers to knowledge of the Māori language. The English requirement is fairly relaxed - no reading and writing is required, just speaking to someone in a functional way. Someone who has been living and working in New Zealand for the necessary five years before applying has probably met that requirement by default.
There is the possibility of making an exceptional-circumstances application that will be considered by the Minister of Internal Affairs. It's not out of the question that a fluent Māori language speaker might be able to make that case in any plausible scenario where it came up, but it would be an exceptional situation.
For visas, again, there are explicit English language requirements for many categories. You might be able to make a similar argument, though it could be an even harder case since the visa rules are primarily focused on economic features. If you had, for example, a skilled job lined up that required fluent knowledge of Te Reo Māori and your native language, or some similar circumstances, you would have a good case.
No part of Te Ture mō Te Reo Māori Māori Language Act 2016 or its predecessor confer a way to substitute that requirement as of right. You could support your argument, in these unusual circumstances, with the principles set out in the Act about advancing, promoting, and protecting the language, but they primarily guide state agencies in deciding their practices and priorities. Because the English-language requirement from the Citizenship Act was left intact, the agency doesn't have the ability to change its policy to that extent, while Immigration might (and hasn't, and successive Ministers and governments have not directed them to).
Pragmatically, the English-language requirement of visas is because it is generally necessary to function productively in New Zealand society at this point, and because for many categories the intent is to fill economic gaps in existing English-language workspaces. It's possible that in future that might change. At the moment it would be creating false hope to suggest otherwise, and for the truly exceptional cases, the exceptional options are available.