Drugs, cash and poker machines have been seized and 12 people have been arrested after raids involving dozens of police in Sydney and New South Wales' Southern Highlands.

Police said Charlee Lloyd, 26, was the alleged ringleader of the group, which was identified as part of a five-month investigation into local drug supplies.

More than 80 officers raided seven properties at Mount Annan, Edmondson Park, Ambarvale, Bowral and Moss Vale on Tuesday.

"During the searches, police located and seized methylamphetamine, more than $30,000 cash, two poker machines, a replica pistol, alleged stolen property and other items consistent with the supply of prohibited drugs," a NSW police statement said.

It is not known how much methylamphetamine was seized in the raids.

Lloyd, who was arrested at Moss Vale, was charged with offences including supplying a large commercial quantity of drugs, directing a criminal group and recruiting a child to carry out criminal activity.

She did not apply for bail when she faced Goulburn Local Court.

Lloyd was remanded in custody and placed on welfare watch due to potential drug withdrawal issues.

Nine other people, aged between 18 and 50, have been charged with a range of offences and are expected to appear in courts today in Goulburn and Liverpool, in Sydney's west.

A 42-year-old man, who was charged with breaching bail, appeared in Goulburn Local Court on Tuesday.

A 17-year-old boy arrested during the raids at Moss Vale will appear at a children's court next month.