There is a catch when it comes to getting a subsidy above the $6m cap.
Under the Commission's rules for the additional grant, every dollar between the first $6m cap up and the higher $20m cap would allow the Commission to acquire an equity share in the film, entitling it to a share of the profits.
According to the Commission's guidance on applying for the grant, this means producers "must provide the NZFC [NZ Film Commission] with a share of net receipts (including profit) from the production".
The share of the profits would be equivalent to half of the equity share the Commission has in the film.
If, for example, the Commission gives "Additional Funding" of $4m in a $20m production - the Commission would get a 10 per cent equity share, entitling it to a 5 per cent share of the profits.
The money wouldn't flow into the Government's core accounts. Instead, the Commission's documents say it will "reinvest all income it receives from the NZFC Equity Share in the New Zealand screen industry".
Act deputy leader Brooke van Velden, who has been a persistent critic of Government film subsidies, said that "New Zealanders will rightly be horrified to learn the Government could profit from an American dramatisation of a terrorist attack that continues to affect many in our community".
"There is no sensible reason for the New Zealand taxpayer to fund this, but it's the logical result of many governments kissing up to Hollywood that Act alone has opposed for years," she said.
The film has come under intense criticism since it was announced last month. The film's New Zealand producer Philippa Campbell dropped out of the production. Ardern has found herself drawn deeper into the production, asking that the film-makers listen to the victims of the mosque attack.
The Film Commission said that questions about the film's funding were "hypothetical" and "assumes we have knowledge of the financial structure of the film".
"The film-makers have not applied for the Screen Production Grant (NZSPG) so therefore it is unknown if the film would meet the specific eligibility criteria."
The financial structure, if it exists, is yet to be made public.
"The NZFC has not received any applications for the NZSPG for They Are Us, nor has it received any applications for development or production funding," it said.
The production has courted further political controversy with three National MPs, Louise Upston, Melissa Lee and Simon O'Connor writing to Labour's Angie Warren-Clark, calling on her to request Arts and Culture Minister Carmel Sepuloni to come before the committee with her officials to explain the extent of the Government and Film Commission's role in the film.
Recent requests for official information have shown the Commission knew about the film just months after the March 15 attack.
O'Connor said "the question remains why details from the NZFC about what they knew and when keeps changing and consequently how can New Zealanders have any confidence that we now have the full story".
The film's producers have been approached for comment.
