One of Sir Peter Jackson's companies is bankrolling an iwi group pursuing legal action over Wellington's Shelly Bay.
Court documents reveal WingNut Films, of which Jackson is a director, has agreed to meet certain costs over and above those met by the plaintiffs.
Mau Whenua is challenging whether iwi-owned land at Shelly Bay should have been sold to developers.
It says it's a group within Taranaki Whānui representing those who voted not to sell the land, those who have reconsidered their position on the sale and no longer support it, and those who say they didn't get a chance to vote in the first place.
The donation agreement outlines that WingNut Films must not interfere with, meddle in, or otherwise influence the proceedings.
It also states the company has no claim over, or right to, any recovered amounts by way of damages.
Jackson has been approached for comment.
The proposed development to give what's known as the jewel in Wellington's crown a new lease on life includes about 300 homes, a boutique hotel and a large village green.
Mau Whenua alleges the 2017 land sale failed to get the necessary support from 75 per cent of iwi members to go ahead.
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The group was incorporated on April 17 this year, according to the Companies Office.
"Under legal advice, we recently formed an incorporated society as a vehicle to take the legal action on behalf of iwi members," a spokeswoman said at the time.
Just a few months later it filed legal proceedings in the High Court at Wellington in a bid to have land at Shelly Bay returned to the ownership of Taranaki Whānui iwi.
Mau Whenua has refused to identify the group's donors in the past.
"I don't think it would be ethical to do so without seeking permission from them first. We have a number of donors, both individuals and groups," a spokeswoman said.
There was a process for significant donations where both parties signed an agreement that the donors would have no say in actions taken by Mau Whenua, she said.
"In other words it's a guarantee to us, because our members were concerned if we were getting reasonable donations that people would try to influence us."
Jackson has also given money through his companies to now mayor Andy Foster's election campaign. The pair have been vocal critics of decisions behind the controversial proposed development at the bay.
Earlier this year at least $250,000 worth of donations were revealed on the books of Enterprise Miramar, a group that has led both previous court cases over the proposed development at Shelly Bay.
But the names of those bankrolling Enterprise Miramar remain to be seen.
Enterprise Miramar chair Thomas Wutzler said a lot of donations they received were confidential.
"I prefer not to be across it because I think it's important I'm not too close to what money comes and where it comes from.
"Sometimes people think if they donate a sum it gives them some sort of influence with us, I'd rather just not know."