FFA boss David Gallop has praised the changing attitudes towards the use of flares at A-League games after Melbourne Victory fans dobbed in the person responsible for an incident during Saturday's derby.

Despite a bumper start to the new season on the pitch, the A-League earned another black eye on Saturday night when a flare was let off inside Docklands Stadium during Melbourne City's 4-1 win over Victory.

The perpetrator, who was sitting in the Victory supporters' bay. was arrested after being pointed out by the club's fans and is facing charges.

While acknowledging the club and league were still grappling with the issue, Gallop said attitudes were changing.

"I think we definitely saw on Saturday night the reaction was 'identify the guy, get him out of the ground', the crowd booed, those are signs that we wouldn't have seen in the past," Gallop said on Monday.

The incident could lead to the club being deducted competition points after Gallop said the Victory had been issued with a show-cause notice.

The Victory and Wanderers were last year hit with suspended three-point penalties following similar incidents.

Victory fans during the A-League's Melbourne derby. ( AAP: Joe Castro )

The FFA last week issued the Western Sydney Wanderers with a show-cause notice after flares were lit by the club's supports group the Red and Black Bloc during their clash with Sydney FC.

The FFA extended the deadline for the Wanderers' suspended three-point penalty until the end of the 2016-17 season and the Victory could face similar sanctions.

"Although there were incidents of flares, we saw wholesale booing, Melbourne Victory fans identified the perpetrator and I think those are positive signs," Gallop said.

"But we've got to stay serious about the fact we don't want to see flares in the game.

"We've got to stay vigilant but there's certainly some positive signs that the whole game is embracing the idea that we don't have flares inside our grounds."

AAP