Tahu, 30, has been without a club since being released from his Eels contract at the end of last year after suffering two seperate race rows.
The first saw him walk out on a NSW Origin Camp after allegedly racist remarks from coach Andrew Johns.
Just months later Tahu was himself accused of the same act against a teenage player in a friendly tournament.
Tahu has represented Australia at both rugby union and league, and will add size and speed to the Panthers’ midfield.
The Panthers have confirmed Tahu will not get a chance to face his old Parramatta team mates in Friday’s round two blockbuster.
He will also be missing from Penrith feeder club Windsor Wolves’ match with Balmain Tigers.