Here's a PDF of the Book of Mormon in Maori:
https://www.lds.org/bc/content/shared/c ... 06_mri.pdf
As you can see, the PDF is based on a scan, so I'm not sure if there is a true digital version of the text. I imagine that if and/or when the Church prepares the text for a true digital release, they will also do other updates like adding footnotes and study helps. In other words, there's a lot of work that would need to go into the process and Maori isn't a common language in the Church yet, so I wouldn't expect a true digital format (such as having the text on LDS.org or in Gospel Library) anytime soon. It's possible that they will update the style to match more contemporary Maori.
Welsh is in a similar situation, with a reviving language and an older Book of Mormon.
All that said, there has been a reemphasis to get the scriptures online in more languages, with a target date for "most languages" being the end of 2016. See this article:
https://www.lds.org/church/news/scriptu ... s?lang=eng
If you haven't seen already, you may also be interested in the Maori hymnbook, which was recently released as a PDF here:
https://pacific.lds.org/maorihymnbook