Greenberg insisted Roberts fly to Sydney earlier this week for a face-to-face at NRL headquarters to discuss an alleged incident involving the Broncos centre and a woman at a Gold Coast nightclub.

Roberts escaped official sanction after the nightclub manager refused to hand over CCTV footage of the incident to the NRL.

Key witnesses also refused to speak with the integrity unit.

But that did not stop Greenberg from making it clear the 23-year-old was on his last warning.

Quite simply, if he stuffs up, he will be banished from the game.  

"The meeting was aimed at encouraging him to make the right choices going forward," an NRL spokesman told AAP.

Roberts was sacked by Penrith and South Sydney for off-field indiscretions.

He was fined $20,000 by the Broncos last year for allegedly abusing a female staff member at a Brisbane pub before being evicted from the premises.

He spent time at a rehabilitation facility at the end of last season, and, following his latest incident, is now under a total alcohol ban.