NRL chief Todd Greenberg admits the code has deep concerns about the declining numbers of rugby league players in Australia.

The issue is at the heart of a row between NRL clubs and distribution of funding from the $1.8 billion television deal that threatens to claim the scalp of ARL chairman John Grant.

It’s understood representatives from all 16 clubs have signed a letter calling on Grant to resign in the wake of his decision to back out of an in-principle agreement to fund clubs at 130 per cent of the salary cap.

Greenberg is backing Grant and says his priorities remain the same as the day he was ushered in as NRL chief executive in March.

“I made it clear on day one in this job that I had two priorities: I want to see more people playing the game and I want to see more people watching the game and growing the base of our participation’s important,” Greenberg said on Thursday.

“We’re seeing some declining trends in the last past few years of the registered participants playing tackle footy.

“We’re seeing great growth in the women’s game, we’re seeing great growth in the recreational game, but we’ve got some great concerns about where we’re heading.”

Greenberg said rugby league wasn’t the only sport with concerns about participation trends.

“So what that means is we’ve got to think very carefully about our strategy and we’ve got to think very carefully about where we apply funds, whether it’s in regional areas in the bush or whether it’s in the city.

“We’ve got to be very, very careful about what we do next.

“We’re going to have some difficult discussions with clubs about funding.”