Ireland flanker Sean O'Brien is the subject of an IRFU investigation into an alleged incident following Leinster's Guinness Pro14 title win two weeks ago.
A source close to the process confirmed to the Sunday Independent that the investigation could last up to a fortnight.
It is alleged that O'Brien urinated on a man in a packed Dublin city-centre pub where some of the Leinster squad were celebrating the title win on Sunday, May 26, the day after the game.
Sean O'Brien is due to have a hip operation which will rule him out of this autumn's Rugby World Cup, at which point his Ireland contract expires. He is due to start a three-year deal with London Irish when he regains fitness.
The alleged incident involving O'Brien followed a separate incident the previous night or early hours of Sunday morning when a player from Leinster's academy was hospitalised.
The player was allegedly knocked unconscious by former Leinster player Stan Wright, who was in Ireland for a reunion with team-mates from the province's first Heineken Cup success in 2009.
He stayed in Dublin to complete both legs of the reunion - on the Tuesday and Wednesday - and returned to New Zealand a couple of days after the reunion.
Wright, originally from the Cook Islands, declined to comment but the Sunday Independent understands that he has apologised to the Academy player.
Leinster issued the following statement on the incident last week.
"An internal investigation was carried out by Leinster Rugby, which has concluded to the satisfaction of all parties and as a result we will not be making any further comment on the incident other than to confirm that the player in question received medical attention and that he has made a full recovery."
The IRFU issued a statement last weekend stating that it "condemns, and is committed to eliminating, any anti-social behaviour within the game, at all levels, and continues to work closely with our colleagues in Rugby Players Ireland on education and awareness programmes for our players".
There was no response from O'Brien's agent.