Keanu Reeves in "The Matrix Reloaded."

Filmmaker Andy Wachowski and his transgender sister Lana are facing a $300 million lawsuit over allegations they stole the premise for their two The Matrix sequels.

The directing duo has been accused by Thomas Althouse of copying the ideas for The Matrix Reloaded and The Matrix Revolutions from a script he claims to have submitted to executives at Warner Bros. Pictures, the studio behind the franchise, in 1993.

Althouse, whose work was titled The Immortals, never heard back from Warner Bros. bosses and alleges he didn't realise the similarities between the work of the Wachowskis and his own script until he checked out the Keanu Reeves films in 2010, seven years after the two sequels were released.

In his legal papers, obtained by editors at TMZ.com, Althouse suggests the plugs in the back of the characters' necks and robotic agents dressed in suits were among the ideas lifted from his screenplay.

Warner Bros. heads and producer Joel Silver have also been named as defendants in the copyright infringement battle, alongside Andy and Lana Wachowski, formerly known as Larry.

In addition to his $300 million demand, Althouse is requesting a share of the $1.63 billion the trilogy grossed at the global box office.