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 Union of Farmers organised the event as a protest about delays in distributing EU farm payments.
It was changed to be about "wider rural economy and food chain issues" after the Scottish government pledged Â£200m to support farmers in the interim.
Scottish ministers Richard Lochhead and John Swinney,  and Scottish Tory leader Ruth Davidson addressed the rally.
Farmers have been hit by delays in processing Common Agricultural Policy payments due to problems with a Â£178m computer system set up to administer the newly-reformed system in Scotland.
The Scottish government said 59% of payments have now been made.
Some protestors called for Rural Affairs Secretary Mr Lochhead to resign, as he told them "we'll get the payments out, we'll fix the problems."
He said: "While we have robust political debate inside the chamber, all political parties agree that food production in this country is an absolute priority.
"Helping out our food producers in their hour of need, whether that's because of the issues we've had with payments or the weather, or because of low market prices, we have to do what we can to make sure that the skills you represent and the jobs you sustain and the support you give to Scotland is maintained going forward."
Scottish Conservative leader Ruth Davidson urged the protestors to keep up the pressure on the government.
She said: "If this had been an issue affecting urban Scotland it would have been solved months ago.
"There's a real question of what happens now. There's still a real question over next year's claims, given we know the computer system doesn't work."
Scottish Lib Dem leader Willie Rennie told the protestors that the Scottish government needed to "act quickly to get the money out the door", while Finance Secretary John Swinney told them "your voice has been heard".

Reading's Danson, who has scored 89 international goals, suffered a hand injury in February and missed Test series against Australia and Germany.
Great Britain play the Dutch in Amsterdam on Tuesday and Thursday.
"We're looking forward to testing ourselves against the number-one-ranked team," said GB coach Danny Kerry.
East Grinstead's Laura Unsworth and University of Birmingham's Lily Owsley are also fit again after injuries and included in the 20-strong squad.
"It is good to have Laura, Alex and Lily back after long periods of injury and it will be good to have competitive match play to help bring them up to match speed," added Kerry.
England came from 2-0 behind to beat the Dutch on penalties to win the EuroHockey Championships in August, with Danson picking up the player of the tournament award.
Maddie Hinch (GK), Emily Maguire, Shona McCallin, Sam Quek, Nicola White (all Holcombe); Kirsty Mackay (GK), Sophie Bray, Laura Unsworth (East Grinstead); Giselle Ansley, Georgie Twigg, Hollie Webb (Surbiton); Alex Danson, Kate Richardson-Walsh, Helen Richardson-Walsh (Reading); Joie Leigh (Clifton); Hannah Macleod, Ellie Watton (St Albans); Lily Owsley (University of Birmingham); Susannah Townsend (Canterbury); Crista Cullen (unattached).
The National Rugby League is being investigated by Australian police over allegations of match-fixing.
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Dozens of farmers gathered outside the Scottish Parliament for a rally highlighting rural issues.
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Striker Alex Danson has been included in the Great Britain squad for their two Test matches against world and Olympic champions Netherlands.