On the eve of the A-League’s Sydney Derby, NSW Police have pleaded with fans to “focus on football, not on causing trouble”.

A heightened police presence will be at the game, which is expected to attract about 40,000 fans to Sydney Football Stadium, in the wake of sanctions handed down to the Western Sydney Wanderersafter their fans lit flares and detonators during a clash with Melbourne Victory two weeks ago.

Last week’s Melbourne Derby also saw flares ignited in the crowd at AAMI Park, prompting more club sanctions from Football Federation Australia (FFA).

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A statement from NSW Police on Friday said it expected most fans to behave themselves on Saturday, but they would “deal swiftly with any criminal and anti-social behaviour”.

“Inside and outside the stadium, there will be a highly visible police presence before, during and after the match,” Surry Hills local area commander superintendent Tony Crandell said.

After accepting the punishment from the FFA, Western Sydney chief executive John Tsatsimas pleaded with fans not to resort to hooliganism and said it would be foolish not to put more stringent measures in place for this weekend’s derby.

Saturday night’s police operation will involve dozens of officers from Surry Hills and the Central Metropolitan Region, along with specialist police units.

They will be searching members of the crowd for any contraband, “including flares and other incendiary devices”.

“Anyone caught with these items will be banned from the stadium. They could also be fined $5,500 and jailed for up to two years,” Crandell said.

“Setting off a flare outside its authorised use attracts even harsher penalties and we remind people this behaviour is not only illegal, it is highly dangerous.

“A lit flare burns at a temperature hot enough to melt steel; we have already seen a number of instances where patrons and a security officer were burned by flare ignitions. It can also cause crowd panic.”

In addition to any legal ramifications, fans caught lighting flares could find themselves in hot water with the FFA, which recently announced its new guidelines for dealing with anti-social behaviour by A-League supporters.