The 24-year-old, whose side were knocked out of the Rugby League World Cup with a loss to Samoa last weekend, was reportedly involved in an altercation with Ireland international James Bentley.
Radley was part of a group of England players who returned to their Manchester hotel after their 27-26 semi-final defeat in London.
The Irish side, in which Leeds forward Bentley featured, were knocked out of the tournament at the group stages.
Bentley was invited to the England hotel where a number of the squad's NRL-based players were staying before returning to Australia.
After being asked to leave, Bentley and Radley are understood to have become embroiled in an argument.
"The RFL have been made aware of allegations and are currently investigating the matter," the RFL said in a statement.
Radley was not the instigator according to sources with knowledge of the situation but the Roosters forward has found himself in hot water for a number of off-field incidents in recent years.
Earlier this season he was summoned to speak with NRL chief executive Andrew Abdo after making a lewd gesture on television.
He was also investigated by the NRL's integrity unit after being thrown off a Sydney to Gold Coast flight last year and following an altercation in Byron Bay over Christmas 2020.
14°C