Five men have been charged over a multi-million dollar cocaine dealing network allegedly operating in Sydney's west and south-west.

The Middle Eastern Organised Crime Squad has been investigating the group for a year.

They believe the group has distributed $10 million worth of cocaine across Sydney.

Officers raided 11 properties about 9:00am (AEST) yesterday at locations including Georges Hall, Villawood, Condell Park, Fairfield, Chester Hill, Granville, Breakfast Point and Yagoona.

Police say cocaine, a smaller quantity of cannabis, a rifle, shotgun, ammunition and $250,000 cash were among the items seized during the raids.

Six men, aged between 25 and 40, were arrested during the raids.

A 25-year-old man was released after questioning.

Four of the men have been charged with supplying a large commercial quantity of a prohibited drug and participating in a criminal group.

They were held in custody overnight to face court today.

The sixth man, aged 40, was charged with supplying a prohibited drug and firearm offences.