The AFL on Sunday announced multiple players from Essendon and one player from another AFL club were being investigated for the use of performance-enhancing drugs.
It came after federal Justice Minister Jason Clare said clubs from both codes involved in the Australian Crime Commission report could now out themselves.
But the NRL said it was yet to inform those clubs involved in the probe into the use of banned substances and links with organised crime within the code, and hoped to do so within the next two days.
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Though even once they have been told, it will be up to the individual clubs to decide whether to go public.
"The NRL is in close and productive negotiation with the Australian Crime Commission to establish a formal mechanism by which we can inform individual clubs that they have been the subject of intelligence gathering by the ACC," the NRL said in a statement released on Sunday.
"Tony Whitlam QC is today continuing to assist the NRL in establishing a formal set of procedures with the ACC through which information can be passed to the clubs.
"This framework should be established in 24-48 hours.
"Once this information is passed on the NRL will not, under the guidelines outlined by the ACC, be able to identify the clubs publicly.
"This will be a matter for the individual clubs to consider in consultation with ASADA (Australian Sports Anti-Doping Authority), the ACC and the NRL.
"While acknowledging media speculation about the number of clubs today, the NRL remains bound by strict legal constraints and these have been reinforced today by both the ACC and Justice Minister Jason Clare."
News Limited on Sunday speculated that six clubs were involved as part of the ACC's investigations.
