The NRL has been made aware of a number of serious matters involving the alleged use of illicit substances.
The NRL Integrity Unit will work with all the parties involved to understand the nature of the allegations and what consequences may flow under the NRL rules if the allegations are determined to be accurate.
"The Game has taken steps over many years to highlight the risks associated with the use of illicit drugs," NRL CEO Todd Greenberg said.
"We will continue that work but ultimately individuals are accountable for their own choices, and the League's capacity to eliminate the use of illicit drugs by its participants faces similar challenges to that faced by society."