Football Federation Australia (FFA) has hit Melbourne Victory with a show cause notice following incidents involving a selection of supporters before and during Saturday's derby against rivals Melbourne City.
Victory fans let off flares inside AAMI Park just days after fellow A-League club Western Sydney Wanderers were fined 50,000 Australian dollars and handed a suspended three-point deduction for the actions of their fans at Etihad Stadium on February 6.
City goalkeeper Thomas Sorensen also had bottles thrown at him by Victory fans after a controversial decision saw Gui Finkler denied a goal, which would have given the reigning champions a 3-2 lead at the time.
FFA chief executive David Gallop said he was "shocked" by the actions of the Victory fans on Saturday.
"FFA has today issued Melbourne Victory with a show cause notice after receiving detailed information from Victoria Police and others that identifies some Melbourne Victory supporters as taking part in actions that have cast a shadow on football," he said.
"The timing of these incidents has shocked many people given the acute focus on these issues. No one could have missed the fact that FFA, our clubs, players and coaches have been explicitly clear in our condemnation of actions over the last week around the ignition of flares.
"We must continue to hold the safety and enjoyment of true football fans at the heart of our decisions.
"The reaction of a section of Melbourne Victory fans, players and coaches on Saturday night has again sent a clear message that this minority is not welcome."
Victory have until 17:00 local time (06:00 GMT) on Wednesday to show cause why they should not face sanction for bringing the game into disrepute.