A film called "They Are Us" is being planned about the attacks on two mosques by a white supremacist gunman on March 15, 2019, in which 51 people were killed, the Hollywood Reporter said last week.
The magazine described the film as an "inspirational story" about Ardern's response to the violence.
Ardern's office said last week she and the government had no involvement with the film. Asked about it at a news conference, she said the Muslim community should be at the centre of any film about the shootings, not her.
"This is very raw event for New Zealand and even more so for the community that experienced it," Ardern said.
"I agree that there are stories that at some point should be told from March 15. But they are the stories from our Muslim community so they need to be at the centre of that. I don't consider mine to be one of the stories that needs to be told," she said.
She said, however, it was not for her to say whether a project should go ahead or not.
The film's title is drawn from Ardern's words on the day of the shootings. The 40-year-old leader's compassionate response united her shocked country and was praised globally.
New Zealander Andrew Niccol would write and direct the film, the Hollywood Reporter said. It quoted him as saying it was not so much about the attacks but Ardern's handling of it.
But some Muslims questioned the plan to make a film when the pain of victims' families, friends and the wider community was still so raw. They also questioned the plan to focus the film on the prime minister and not the victims.
Muslim community advocate Guled Mire told the 1 NEWS network that he thought the film was "distasteful".
"It completely feeds into this white saviour mentality," he said.
Armed with high-capacity semi-automatic weapons, Australian Brenton Tarrant killed the 51 people and injured dozens when he opened fire in the two mosques during Friday prayers in Christchurch.