It is understood the games under investigation are Manly v Souths round 16 last year and Manly v Parramatta round 24 last year. Manly lost both games 20-8 and 20-16 respectively.
The NRL said today it was co-operating with authorities in relation to information regarding allegations of match fixing.
NRL chief executive Todd Greenberg has vowed to inflict the toughest penalties possible for any player or official involved in match-fixing.
In an email sent to all 16 club chief executives this morning, Greenberg issued a powerful message of zero tolerance, explaining that the game's integrity was at risk as a result of a NSW Police investigation into possible match fixing wthin the NRL.
"The NSW Police have this morning made public comment that they are in the early stages of assessing information on possible match fixing within the NRL," Greenberg wrote.
"The possibility of the existence of match fixing within our sport cuts to the core of our sport and our values.
"We will take whatever action is necessary to protect the integrity of our sport."
Greenberg plans to also provide further detail surrounding the investigation to all 16 club CEO's during a 3pm phone hook-up this afternoon.
In a statement the Rugby League Players Association stated it was committed to working with authorities, the NRL and clubs to protect the best interests of the game and players in the wake of allegations of match-fixing.
"The RLPA is concerned about any suggestion of conduct detrimental to the integrity of the game," the statement said.
"It is important people respect the presumption of innocence principle and avoid prejudgement and speculation in relation to any allegations subject to the police process."
More NRL players are also expected to be issued with warnings against consorting with convicted criminals as police grow increasingly concerned about underworld figures infiltrating major sporting codes with the intention of match fixing.
The Organised Crime Squad is close to finalising additional warnings after Parramatta duo Corey Norman and Junior Paulo and Penrith's James Segeyaro were issued notices last week. There is no suggestion the men were engaged in or intended to engage in match fixing.
There is a growing concern among senior Organised Crime Squad detectives that the NRL has already been infiltrated and clubs are in denial.
Detective Inspector Wayne Walpole, in charge of the state's charter against organised crime infiltrating sport, said the infiltration had happened.
"I'm not saying corruption or match fixing has happened, but I'm saying the infiltration is there and that infiltration can lead to the compromise of the sports of the athlete," he said.
If these new allegeations prove true this won't be the first time the NRL has become embroiled in a match-fixing scandal.
Former Bulldogs player Ryan Tandy was convicted in 2011 of trying to fix a 2010 match between his side and the Cowboys.
Tandy was fined $4000 and placed on a 12-month good behaviour bond, the magistrate presiding over the case saying he was clearly involved in a plan to make money off the first scoring play of the game.
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