Mario Tartak, who represents such players as Josh Addo-Carr, Damien Cook and Haumole Olakau'atu, is alleged to have communicated with an underage player without a parent or guardian present.
The NRL also claims he "entered into a commercial arrangement with two NRL clubs", which is a breach of the league's accredited agent scheme rules.
Tartak has been offered a 12-month suspension and $25,000 fine, with the NRL factoring in previous breach proceedings when considering his punishment.
The agent received a breach notice from the NRL in 2019 for failing to disclose bankruptcy proceedings.
A second agent Matthew Desira has been offered a six-month ban and $10,000 fine.
The NRL claims the agent of Wests Tigers coach Benji Marshall did not disclose "police charges and court proceedings" brought against him.
The two agents have five days to respond to the breach notices.
By Thursday night, Tartak had already engaged legal representation and planned to fight the claims.
The pair's suspensions would have the potential to cause headaches for players off contract this year, as well as those who will become free agents on November 1 ahead of their deals ending next season.
Tartak's clients Addo-Carr, Cook, Nathan Brown and Luciano Leilua are among those off contract in 2026, while Danny Levi and Josh Schuster headline his list of players with deals expiring this year.
Players can still be managed by other agents that operate out of the same company as Tartak and Desira.
Elsewhere, the NRL has issued Des Hasler with his final warning for criticising the match officials after the Gold Coast coach singled out a bunker referee in round 13.
Hasler has become the second coach this season to receive an official final warning from the league after North Queensland boss Todd Payten last month.
"Mr Hasler has been reminded of his obligations under the NRL Rules and Code of Conduct as well as his general responsibility as a sporting leader," read a statement from the NRL.
"Negative public remarks about match officials significantly hinder the recruitment and retention of match officials at the community and pathways tiers of the game.
"All rugby league participants are reminded to respect match officials who perform a vital role within the game."
Asked about his comments ahead of Saturday's clash with Brisbane, Hasler said: "I was just pointing out a few things."
Hasler was frustrated with a pivotal decision in the second half of his side's 28-16 loss to Melbourne last week and promised then to seek clarification from the NRL.
Titans hooker Sam Verrills was denied a try on the grounds he had made contact with teammate Tino Fa'asuamaleaui as he attempted to burrow past Melbourne defenders lying in the ruck.
Bunker official Kasey Badger ruled Storm fullback Ryan Papenhuyzen had been denied the chance to tackle Verrills because of this contact, with the Storm scoring their match-sealing try minutes later.
"Kasey got it wrong, again," Hasler said then of the call.
"There's an email from the NRL about players lying in the ruck; that's fine, let them lie in the ruck, but you shouldn't lose the advantage.
"They were lying all over the ground and six again, penalty, I don't know whether it was called, and young Vez (Verrills) picks up the ball and dives through, doesn't touch anyone, (Storm fullback Ryan) Papenhuyzen wasn't obstructed.
"That was the word-for-word what the NRL sent out so I'll be interested to see what their explanation was."
