The NRL acted after its integrity unit viewed CCTV footage of an alleged assault by the 29-year-old former St Helens full-back on his partner.
Barba, the leading try-scorer in Super League in 2018, was sacked by his new club, North Queensland Cowboys, without playing a game following the alleged incident outside a Townsville casino last weekend.
NRL chief executive Todd Greenberg said the integrity unit probe found “there was a physical altercation between the player and his partner”.
“His registration with the game is no longer and I can’t see a time, at any time in the future, that he’ll be welcomed back,” said Greenberg.
The Rugby Football League previously said it would uphold any ban imposed by the NRL and that stance has been adopted by Super League chief executive Robert Elstone.
Speaking before the NRL’s announcement that Barba had been deregistered, Elstone said: “I think we have two duties. One, to stand shoulder-to-shoulder with the Cowboys and the NRL and also we have a duty to our own competition.
“So, in light of not knowing all the circumstances, it is almost impossible to see a way back for Ben Barba, back into Super League.
“The decisiveness of the Cowboys’ actions suggest there is something significant of wholly inappropriate behaviour.”
In 2017, the RFL rejected an appeal by St Helens against a 12-match ban imposed by the NRL on Barba for cocaine use in the aftermath of Cronulla’s 2016 NRL Grand Final triumph.
Sacked by Cronulla, Barba had a brief spell in rugby union with Toulon before being snapped up by St Helens in May, 2017.