Injured Broncos star Kotoni Staggs has been served a preliminary NRL breach notice over an altercation at a Dubbo hotel last year.

Staggs was not charged by police over an incident in which two of his friends and former junior football teammates pleaded guilty to assault causing bodily harm.

The Brisbane centre is alleged to have provoked the altercation in court documents that left the victim with minor head injuries.

The NRL Integrity Unit has conducted an investigation into the November 6 incident, issuing Staggs a preliminary breach notice.

Under the terms of the notice, Staggs is facing an undisclosed fine and must meet with NRL CEO Andrew Abdo and the Integrity Unit, while also completing relevant education courses before he will be approved to play again in the NRL.

Staggs is not expected to return from an ACL rupture until midway through the 2021 season.

"The NRL has issued Kotoni Staggs with a preliminary breach notice in respect of his involvement which he is currently responding to," an NRL spokesman said.

"The breach notice proposes a fine and that Kotoni be required to complete appropriate education and meet with the NRL CEO and Integrity Unit before playing in the 2021 season."

Staggs, 22, had a breakout 2020 campaign cut short by his serious knee injury, but not before earning Dally M Centre of the year honours.

He is also coming off contract after opting to go to market for 2022 rather than take up a Broncos player option in his favour.

Brisbane officials have been contacted for comment but have not yet made a statement on the matter.