The notice relates to alleged breaches of the rules relating to gambling on NRL matches.
Simona will now be prohibited from training or playing with the club until the matter is finalised.
He will be given a chance to respond to the allegations before a final determination is made.
The NRL will not be commenting further until the matter is resolved.
The Wests Tigers have released the following statement:
Wests Tigers have been made aware that player Tim Simona is currently under investigation by the NRL Integrity Unit in regards to allegations of breaches of the rules relating to gambling on NRL matches.
The Club will be making no further comment until the investigation is complete.