The banner of a blue-faced man giving oral sex was shown for several minutes during the match at ANZ Stadium, which was attended by almost 45,000 people, many of them families with young children.

It was eventually confiscated but the image was also posted on the Twitter account of the club's supporter group, the Red and Black Bloc.

Football Federation Australia condemned the image as “discriminatory” and “totally unacceptable” and indicated that further action is likely.

It’s not the first time the club has faced disciplinary action over the conduct of fans, with the Wanderers currently sitting on a suspended points deduction for the use of pyro in the stands.

It's over! Wanderers end Sydney's unbeaten run

Emotional Santa proud of Wanderers

Ref sorry for derby penalty blunder - reports

A-League chief Greg O’Rourke told AAP: “FFA is aware of the unauthorised and totally unacceptable banner that was displayed in the Western Sydney Wanderers area during Saturday night’s Sydney derby at ANZ Stadium.

“The discriminatory nature of the tifo has no place in society and will not be tolerated in the A-League.

“We are working with the club and currently gathering as much information as possible and will deal with the matter when we have all available facts including CCTV footage.”

In a statement to AAP chief executive John Tsatsimas said: “Due to the inappropriate nature of the item it was swiftly removed by our supporter management team and disposed of.

“As a club made up of the most diverse and inclusive cross-section of members and fans in Australian sport, we do not condone the imagery depicted in the banner.

“The club remains committed to working with FFA and our stadiums to ensure our matches remain a positive, family-friendly environment.”