Inglis is understood to have struggled to adapt to retirement from his playing since giving up the game just a matter of weeks ago.

He is understood to have gone missing during the NRL's Magic Round in Brisbane earlier this month, sparking the current serious concerns for his welfare.

In January he escaped without a conviction on a drunk-driving charge but was still stripped of his captaincy of the Kangaroos over the incident last October.

Today Sydney Souths confirmed their former captain had "...entered a facility to undergo treatment to assist and support his mental health.

"On behalf of Greg and his family, we ask the media and the public to respect their privacy," a statement from the Rabbitohs said.

South Sydney's 2014 Premiership-winning captain was forced out by recurring injuries after playing just two games this season.

But he stayed in the sport in a series of roles with Souths as an assistant coach and backroom roles in the  the club’s commercial division and charity arm Souths Cares.

However it is said none of it could replace the thrill of his playing career.

"The best thing I say about Greg is that he's getting the support that he needs," Souths coach Bennett added.

"So that's as much as I want to talk about it, elaborate on it. But that's the situation."