Police have uncovered information about tax evasion, money laundering, spot betting and possible salary cap breaches within the NRL, the ABC understands.
The information was discovered as part of the New South Wales Organised Crime Squad's investigation into the influence of organised criminal groups in match fixing allegations within the NRL.
It is understood detectives from Strike Force Nuralda have so far found no evidence of systemic match fixing involving organised crime groups and NRL clubs.
There is evidence some players and officials from a number of clubs have links to organised criminals who may exert some influence over the individuals.
However, detectives have not found evidence that NRL clubs and criminal groups were "getting together to throw matches".
But it is believed police have found evidence of insider betting where players and officials have allegedly passed on information to punters.
These allegations date back to 2015, and there is a six-month statutory limitation on the offences, meaning police can no longer lay charges.
Despite the fact it is unlikely charges will be laid, the ABC understands police will pass this information on to the NRL when they complete their investigation.
The probe has previously focused on three Manly Sea Eagles matches in 2015, but it is understood it is now examining problems across the entire NRL.
The Organised Crime Squad, with the help of the NSW Crime Commission, is speaking to players, referees and club officials.
It is understood some players and officials will not talk while others are cooperating.
he ABC understands third-party payments were promised to some Manly players, but were not followed through, and some players subsequently left the club.
Manly co-owner Scott Penn told the ABC the allegations were unfounded but he would fully cooperate with the authorities if needed.
Penn confirmed NRL CEO Todd Greenberg had informed him of the allegations.
In a statement, the Sea Eagles said "there are no allegations in relation to any irregularities with regard to the club's salary cap".
"The club has zero tolerance for inappropriate behaviour and if any charges or substantive claims are made we will tackle them head on."
An NRL spokesperson it said the organisation was "not in possession of evidence of any violations which would warrant any disciplinary action".
"However, we are in constant dialogue with police and will take action if it is warranted."
NSW Police will not comment on the investigation except to say that Strike Force Nuralda is continuing its inquiries.