DETECTIVE work by an Australian online poker player has uncovered a $US10 million cheating scandal at two major poker websites and triggered a $US75 million ($A93 million) legal claim.

- Australian uncovers online poker cheating

- Player accounts 'won money too fast'

- Site owners file $US75m legal claim

Australian Michael Josem analysed detailed hand history data from Absolute Poker and UltimateBet and uncovered that certain player accounts won money at a rate too fast to be legitimate.

His findings led to an internal investigation by the parent company that owns both sites. It found rogue employees had defrauded players over three years using a security hole that allowed the cheats to see other players' secret (or hole) cards.

Now the owners of the sites have filed a $US75 million claim against the makers of the software that powers them, claiming they were unaware of the security holes when they bought the sites in 2006.