Ngāi Tahu has taken a significant stake in the country's biggest fishing company, Sanford.
The South Island iwi launched a lightening foray in the sharemarket to increase its holding from less than 5 percent to nearly 12.6 percent, paying $5.50 a share, which was 24 percent above Sanford's closing price on Tuesday.
Ngāi Tahu Holdings is now the single biggest shareholder in the fishing company but said it had no intention at the moment to make a full takeover offer.
Sanford chair Sir Robert McLeod viewed the investment as positive.
"Ngāi Tahu is one of New Zealand's largest and most successful iwi investors, with a substantial stake in and knowledge of the seafood sector. This offer recognises the potential long-term performance and quality of Sanford's assets."
Chief executive Peter Reidie said the investment signalled Ngāi Tahu would be a stable, long term, minority shareholder.
"They share our views on sustainability and community - they are focused on the long term and so are we."
Ngāi Tahu Holdings chief executive Mike Pohio said Sanford is a natural fit within its portfolio.
"This is a sector we have extensive experience in, it's a sector we have had a long standing connection in and we see it [as a continuation of that]."
He said Sanford was currently undervalued by the market and the price it paid was a reflection of the company's long-term potential.
Sanford has more than 30 vessels and significant marine farming operations, but this week said it continued to be hit by disruptions in restaurant sales and getting products overseas because of Covid-related difficulties.
The iwi has big interests in fishing and seafood sectors, including quota, farms, and processing, which make up just over 10 percent of its $1.5 billion commercial assets, according to its 2020 annual report.