It's the rumour that refuses to go away.

Cameron Munster is on the radar of R360, the Saudi Arabian-backed rugby union rebel league set to offer players millions of dollars - and certainly more than any NRL club can entertain.

It was reported in October that he was on a 'hit list' of the competition which had double-digit numbers of NRL players in its sights.

News Corp are now reporting he has been formally approached by recruitment executives of the new competition as they investigate star players from the NRL in a bid to help get off the ground all around the world.

Munster has so far not indicated any interest in R360, but he isn't the first player from the NRL to be attacked by the rebel league.

Now released teammate Ryan Papenhuyzen has reportedly been offered big dollars by the competition, former Parramatta Eels winger Zac Lomax was released last weekend to pursue opportunities outside of the NRL, and Payne Haas is also in the process of making a decision on his future after being offered a reported $3 million per year to jump codes to the 15-man game with the new competition, which has been relentlessly and repeatedly trashed by Australian Rugby League Comission chairman Peter V'Landys.

Despite that, there are still real concerns that the NRL will lose a number of stars to the competition.

Munster, despite being approached, would appear an unlikely target.

The Queensland skipper is contracted with the Storm to the end of 2027, and recently reconfirmed his intention to see out that time period despite being linked to the Perth Bears.

Melbourne releasing Jonah Pezet was as clear a sign as any that Munster won't be going anywhere, and the five-eighth is now unlikely to gain a release to head to any other club or competition.

The rugby union competition also has the NRL's threat of ten-year bans hanging over players' heads, while there have also reportedly been concerns expressed in recent times that the financial backing of the competition may be unstable to the point it will never actually get off the ground.