For My Father's Kingdom is directed by Pacific film-makers Vea Mafile'o of Tonga and Samoa's Jeremiah Tauamiti.
The documentary centres on Vea's father, Saia Mafile'o, and his four children.
Film reviewer Chris Schulz told Kathryn Ryan on Nine to Noon people were in tears at the screening in Auckland.
"All great documentaries shine a light on something that you don't know anything about. Right?
"So, this is about tithing in the Tongan church. I knew nothing about this.
"When I walked in, I walked in absolutely cold. And it really affected me.