The 29-year-old former St Helens full-back has been the major try-scorer at Super League at 2018.
He was sacked by his new team , North Queensland Cowboys, on February 1 without playing a game after an alleged assault on his partner in a casino.
Queensland police are investigating the incident.
And Barba looks prone to be prohibited for life by the NRL.
If this occurs, the r-fl say it will uphold the suspension, blocking back a path to Super League.
An R FL statement said:”We can always uphold any ban imposed by the NRL (susceptible to the right of interest our own operational rules tribunal), under a reciprocal agreement involving the RFL and the NRL.
“Independent to this arrangement, the RFL board has the right to deny registration to some player – and also would also check Super League in that procedure.
“We’re bound to follow this process – however, in the event the facts of the case prove to be reported, that the r-fl would condemn them deplorable.”
After failing a drugs test in 20-16, Barba signed for French rugby union side Toulon at February 2017 at a controversial movement that saw him escape sanctioned because the suspension only applied to Rugby league.
The fullback proceeded to Saints three weeks later, but an independent panel upheld your choice to suspend Barba on his return to the sport and he was not able to play for them until August 20 17.