The NRL will reportedly investigate how odds fluctuated wildly prior to the release of information that the Penrith Panthers were set to rest a host of players this weekend.

It was revealed on Monday evening that the Panthers have given up on their push for a spot in the top four and will instead prepare for a four-week run through the finals, where all games will be elimination contests.

Reports suggest a host of players - potentially their entire group of State of Origin players - will not take to the field against the Canterbury Bulldogs this weekend.

The break could have enormous top-four ramifications for the Bulldogs, Panthers, and New Zealand Warriors, with the Panthers set to return to full strength for a final-round hit-out against the St George Illawarra Dragons in Wollongong, ahead of the knockout rounds commencing.

However, it's betting where the NRL integrity unit will be forced to look, with the Panthers opening at odds of $1.60, before ballooning north of $2 prior to the information, which included halfback Nathan Cleary not playing, was released.

It's unclear how many bets bookmakers may have taken on the Bulldogs prior to the markets adjusting, but Code Sports has revealed the NRL's integrity unit is set to investigate, while Phil Rothfield, speaking on NRL 360, said the NRL will be interested in how the information circulated.

“The bookies put the first betting market up with Penrith at $1.60 and the Bulldogs at $2.30. All of a sudden, early this afternoon, Penrith went out to $2.30 and Canterbury out to $1.60,” Rothfield said.

“Then a story appears that Penrith are likely to rest a significant amount of players. How the bookies got the prior information might be of interest to the NRL.

“Either the bookies found out or the punters found out. The bookies can change the price without a lot of money, but I suspect the punters have got on.”

Betting regulations around the NRL are tight, and in accordance with laws, they could request any information they deem necessary in completing an investigation.