NRL chief executive Todd Greenberg is confident embattled Manly have enough resources to remain on the northern beaches for the long-term future.

Coach Trent Barrett's expected departure at the end of the season amid reported concerns over football department resources has raised concerns over the club's viability at Manly.

Sea Eagles owner Scott Penn has vehemently denied a lack of financial support for the club.

And Greenberg said the introduction of a football department cap, as well as annual club grants about $3 million over the salary cap, meant every club should be resourced adequately to be competitive.

Asked whether the NRL funding was enough for Manly, Greenberg said: "Yeah, that's right.

"Ultimately those are decisions for clubs to make about their salary cap, their rosters, their football departments, their revenue generation.

"But make no bones about it - we're in the first year of a five-year strategic cycle for the game.

"We've invested more money into clubs than ever before. Clubs have the very best opportunity in this period of time to be sustainable for the long-term future of the club."

Greenberg admitted he has held numerous talks with Sea Eagles chief executive Lyall Gorman concerning their struggles, and believes the club is merely having a disappointing year.

However, he reiterated the governing body's stance that the game would be unable to save any club should their ownership structure fall over.

"And there's a reason for that - we can't fund them because we haven't got reserve funds inside the game to do what we've done previously. All clubs are acutely aware of that," he said.

Meanwhile, Greenberg also revealed a final decision on holding a NRL season-opener in the United States needs to be made within the next three weeks.

It is understood a "round zero" fixture is pencilled to be played in California.

"We want to make sure that if we could do something innovative like that, which I've said a number of times I'd really like to do, you've got to be able to make the numbers stack up," Greenberg said.

Negotiations for a Test match between Australia and Tonga in New Zealand at the end of the season are also ongoing.

He met with NZRL representatives on Wednesday and hoped to provide an update next week.