"I don't want to know my dad. I'm one of those people, though that like if there's like toxic people in my life, I can just cut them off and that's it. I'm not really dealing with you again," the Kiwi-born NRL star said.
"But I do have this want to know like, what am I? Am I like, English? Am I, I don't know. Like what half-nationality wise."
Benji also revealed the unexpected consequences of a documentary that aired in 2002 when he had just made his NRL debut at the age of 17.
"After I made my debut, I did this documentary thing in New Zealand and said I'd never met my dad and I had 10 emails from people saying they were my dad," he said.
Earlier this week on Celebrity Apprentice, Benji admitted that growing up without a father made him feel like there was something missing.
While reminiscing on his childhood, the 37-year-old said he sometimes felt unsafe in his own home, and even defended himself with a butter knife.
WATCH: Benji and Zoe Marshall's home. Story continues.
"This is a story that I've never told. I've never talked about this publicly. I've never ever talked about this because it means so much to me," he said.
"That's not the real me. You know how I know that? Because I don't even know the real me. There's a half of me missing that I haven't found out about. I don't know my real dad. I don't know my culture. I don't know my nationality. Who am I?"
The former Rabbitohs star is now happily married to his wife Zoe, and the pair share two kids; Fox, four, and Ever, one.
This article first appeared on our sister site, Now to Love.