The NRL is on the brink of scrapping plans to stage its season opener in the United States next year, unwilling to wear a loss of up to $1 million on the match as rugby league's American push stalls.

Fairfax Media understands that unless a white knight emerges within days to help underwrite the event the experiment will be shelved, six months after NRL chief executive Todd Greenberg used the season launch to outline his ambition for a first regular-season match outside Australasia.

American hopes fading: NRL chief executive Todd Greenberg. Credit:AAP

But it is tempered with news there might be an imminent boost for the international game with a New Zealand-Tonga Test match looming to fill the void of the ill-fated mid-year Denver experiment.

The NRL's reluctance to fly head first into the US next year will be a bitter blow for international proponents of the club game who had thrown their support behind the concept.