Halfback Lui has been stood down by the club and will appear in court next month following an incident with his partner Taleah.
A statement from the Tigers read in part: “The Club and the player in question have co-operated fully with the police investigations. Both Robert and his partner Taleah will be offered counselling by the Club.
“Given the nature of the allegation, Robert has been immediately stood down from all Club duties until further notice.
“It is important however that the legal process is now respected by all parties and as such it would be inappropriate for us to be making any further comment at this stage.”