Simultaneous police raids across NSW by almost 150 officers have led to 18 arrests and more than 170 drug charges.

ALMOST 150 police stormed 18 properties across Sydney, the Hunter Valley, Tamworth and the Central Coast at 7am on Friday.

Eighteen people aged between 19 and 69 were arrested during the blitz, in which more than 20kg of cannabis was seized.

Police said on Saturday they had since laid 171 charges relating to the alleged large scale supply of cannabis.

One man, 38, from Bondi in Sydney's east was charged with 60 offences, including 35 counts of supply cannabis.

Meanwhile, a 36-year-old man from Long Jetty on the state's Central Coast was charged with seven counts of supplying cannabis, four counts of supplying a prohibited drug and knowingly participating in a criminal group.

Both men were due to appear in court on Saturday.

The raids were part of an ongoing operation by Strike Force Whitmont, formed in March to investigate the large-scale supply of cannabis.

To date its officers have seized about 40kg of cannabis leaf with a potential street value of $260,000.