Talks have been going on for months between representatives of the Australian and British games but Thursday's news represented the first time a formal offer has been received by Super League.
In a statement, Super League said: "RL Commercial can confirm that a first offer has been received from the ARLC (the Australian Rugby League Commission, which governs the NRL in Australia) as part of the sport's recapitalisation project.
"The Super League clubs have been informed this morning.
"Details of the offer remain confidential."
Super League has made no bones about its urgent need for financial support and wider investment, while the NRL has been equally insistent about its vision to help make the European game stronger in a push to make rugby league much stronger globally.
Some reports have suggested that Super League could receive a huge investment of about $A60 million windfall over the next five years from the NRL, with the Australian league eventually owning 50 per cent of its UK counterpart.
The NRL's former chief executive Andrew Abdo, who's now taken up the same role at Tennis Australia, had been instrumental in the move towards 'globalisation' of rugby league and on a visit to Britain in April, spoke about the NRL's hoped-for involvement in Super League.Â
"We really believe in the globalisation of rugby league," Abdo said.
"This is a great game and we want to take it to as many people as possible. We want to win as many fans as possible.
"So while the game is growing really well in the southern hemisphere, we also want the game to be strong here in the north.
"This is about a partnership where we can collaborate on how we can grow the game, how we can grow revenues and how can those revenues be pumped back into the game.
"That's pretty nuanced and that's something we have to develop together."
The Super League is moving into its business end this season with the playoffs set for next month and the grand final to be held on October 3 at Old Trafford.