Mataora was released by the Canberra Raiders, where he has played 33 NRL games since making his debut in 2010.
The 23-year old prop played his junior football in Queensland before joining the Raiders in 2009, he is also a Cook Islands international.
"Sam was looking for a new opportunity," Recruitment Manager Peter Mullholland said.
"He is young, adds size to our pack, he has a good work ethic and we have no doubt he will want to prove himself at the Knights."
Mataora will join training with the NSW Cup squad this week before joining the full time squad when they return from the bye next week.
CANBERRA RAIDERS STATEMENT:
The Canberra Raiders have released Sam Mataora from the remainder of his current contract to take up a position with the Newcastle Knights for the remainder of the 2014 season.
Mataora was contracted to the Raiders until the end of 2014, but was signed by the Knights on Monday prior to the end of the June 30 transfer period.
The Raiders would like to wish Sam and his family all the best for the future.Like