Guns, ammunition and illegal drugs have been seized in a crackdown by police on the Rebels outlaw motorcycle gang across Sydney.

Officers taking part in Strike Force Raptor raided the gang’s Leppington clubhouse and also properties connected to gang members and associates, over four days.

Eighteen firearms and almost 450 rounds of ammunition were seized and a number of gun licenses were suspended due to unsafe gun storage.

Knuckle-duster weapons were also found as well as steroids, methylamphetamine, cannabis and alcohol allegedly in contravention of liquor laws.

During one of the searches, it is alleged a 46-year-old Rebels member assaulted police.

The man was taken Liverpool Police Station and charged with two counts of assaulting police, and one count of resisting arrest.

In all, 12 gang members including several high-ranking “Sergeant-at-Arms” Rebels will have to face court for 25 offences mostly relating to drugs.

Police also used the opportunity to issue members with court attendance notices for outstanding traffic matters, vehicle defect notices and exclusion orders barring gang members from Melbourne’s Crown Casino.

The four-day operation targeted properties across greater Sydney, from Kingswood to Woodbine and Camperdown.

“Strike Force Raptor was established by State Crime Command’s Gangs Squad in 2009,” according to a NSW Police statement.

“It is a proactive and high-impact operation targeting outlaw motorcycle gangs and any associated criminal enterprises.”

Police say a number of investigations are ongoing and anyone with information relating to illegal activity by Rebels’ gang members is urged to contact police.