Financial crimes watchdog AUSTRAC has told SkyCity Entertainment its Adelaide casino may be seriously lacking in preventing money laundering.
The casino operator on Monday said potentially serious problems had been found in SkyCity's anti-money laundering and counter-terrorism financing controls.
The watchdog will continuing to investigate after assessing how high risk customers were managed at the Adelaide casino in the 2016 and 2019 financial years.
SkyCity said it has not been told what action may be taken.
The regulator has fined companies for not meeting their legal obligations.
SkyCity shares had dropped 4.41 per cent to $3.25 by 1140 AEST.