Lawyers for rugby league great Mark Geyer are threatening to unmask the individual behind the notorious NRL Memes site, which has been posting sex videos of NRL players on Facebook that have subsequently been shared on social media.

The site began publishing videos in January when a video of former Roosters player Dylan Napa went viral, appearing to tell a woman to "Call me Big Papi".

Happier times: Mark Geyer (left) alongside his former Triple M Grill Team colleagues Matthew Johns and Gus Worland.

Mr Geyer said he will sue those behind the Facebook page for falsely identifying his 22-year-old daughter Montana as participating in the latest video involving Panthers star Tyrone May .

On Monday night, the page uploaded a screenshot from one of the videos at the centre of the allegations, with the caption: "The bird in the Tyrone May video is Mark Geyer's daughter. Happy days at Penrith."