Sydney's Daily Telegraph reported the investigation concerns two games involving the north Sydney-based Manly Sea Eagles last year.
It said the games were against South Sydney Rabbitohs and Parramatta Eels.
"The organised crime squad is in the early stage of examining information relating to alleged match-fixing in the NRL," said New South Wales police.
Manly's media department was unavailable for comment, while the NRL said it was co-operating with authorities.
"The possibility of the existence of match-fixing within our sport cuts to the core of our sport and our values," said NRL chief executive Todd Greenberg.
"We will take any action necessary to protect the integrity of the game."
In 2011, Ryan Tandy was banned for life after being convicted of match-fixing while playing for Canterbury Bulldogs against North Queensland in 2010.
Tandy lost an appeal against the charge in 2014. He died the same year, aged 32.
The National Rugby League is being investigated by Australian police over allegations of match-fixing.