The Australian newspaper on Friday published detailed allegations of drug use and domestic violence levelled at Burgess, who retired from playing a year ago but is still employed by the club in a coaching role.
The report included claims that the club allegedly attempted to cover up the misconduct.
The NRL’s chief executive, Andrew Abdo, said the league’s integrity unit would speak to South Sydney officials on Friday.
“These allegations are very serious and I’ve instructed the integrity unit to investigate the claims as a priority. We will also seek the advice of police and other relevant authorities throughout this process,” Abdo said.
“This is new information for the NRL and it is important we now gather the facts. The allegations have not yet been tested and due process will be followed as we undertake a thorough investigation.
“There is no place in our game for violence, harassment or abuse against women. If anyone is found guilty of these allegations we will take the strongest possible action.”
Burgess’s lawyer Mark O’Brien strongly denied all allegations, the Australian reported.
“The allegations are false and constitute an indefensible defamation against my client,” the paper quoted O’Brien as saying.
The chairman of the ARL Commission, Peter V’landys, said the NRL was unaware of the allegations against Burgess and Souths until Friday.
“It would be totally inappropriate to comment on this specific case. I don’t have sufficient facts. Like anyone else in the community, you have to provide due process and natural justice and Sam should be afforded that,” V’landys told Sydney radio 2GB.
“Let me stress that the NRL has a zero-tolerance, and will always have a zero-tolerance, for violence against women.
“But in this instance, I think that the appropriate action is to investigate it, get all the facts, and make a judgment after that.
“Once we have all that information, all the facts, and everybody’s version we will make the appropriate decisions.”
A NSW police spokesperson said in a statement: “On Wednesday 30th September officers from the Hume Police District received a report outlining various allegations relating to the conduct of a 31-year-old man.
“Police have commenced inquiries, however as these inquiries are in their infancy there will be no further comment made at this time.”
Burgess called time on his playing career at the end of last season after two stints with the Rabbitohs, during which he inspired the team to the 2014 NRL premiership, when he famously played on with a fractured cheekbone in the grand final.
He then spent a year away from rugby league, playing union for Bath Rugby and appearing at the 2015 World Cup with England, before returning to Sydney and the Rabbitohs for the start of the 2016 season.
He signed a four-year extension to his contract in 2018, but a chronic shoulder problem ended his career earlier than expected, although he stepped into the role of assistant coach at South Sydney.