The show focuses on a group of people in the future who decide to travel back to prehistoric times to start a new civilisation.
According to Deadline, O'Mara is currently in negotiations about playing Jim Shannon, a father with a shady past who helps his family adapt to their new lifestyle.
O'Mara, who previously starred in the US remake of Life On Mars, would be the first actor to become a cast member.
The series is executive produced by Steven Spielberg, while Alex Graves recently signed up to direct. Filming is expected to begin in Australia at the end of this summer.