Nineteen people have been arrested in early morning raids as part of Strike Force Alistair, a joint operation between police and the NSW Crime Commission targeting organised crime in the state.
And police expect about 30 people to be charged by the end of Tuesday.
Drugs, firearms, a hand grenade and around $500,000 in counterfeit cash have also been seized.
Speaking at Crime Commission headquarters, Detective Superintendent Mick Poltecki said 350 officers were involved in the raids which executed 30 warrants across southwest Sydney, the northern metro area, city, and the south coast.
The operation targeted senior members of the Hells Angels, Comancheros and Rebels, as well as Asian and Balkan crime gangs, police said.
'Today's result has been a tremendous hit to organised crime in NSW,' assistant commissioner Bob Inkster told reporters.
Det Supt Plotecki said a number of people will be charged on Tuesday with commercial drugs supply, firearms offences, providing explosives, and in relation to counterfeiting cash.
The arrests were the culmination of two years of work involving the Crime Commission and police, 95 surveillance warrants, 41 telephone intercept warrants and the monitoring of more than 500,000 phone calls.
He said a key component of the operation was 'targeting those people that make these networks work'.
Det Supt Plotecki said the operation wasn't 'about putting large amounts of drugs on tables'.
'This is about destroying those relationships and those people that make criminal networks function,' he said.
Police Commissioner Andrew Scipione said he was limited in what he could say because the investigation was ongoing, but there would be some surprises ahead.
'You will be surprised by the names that will come out, there are some very very senior members of organised crime gangs, and that will roll out over the course of today,' he said.
'You will be surprised by some of the allegations because these allegations are extraordinarily serious when it comes to firearms, when it comes to drugs.'
Police said a number of people were arrested three weeks ago for conspiring to import 400kg of amphetamines, also as a result of Strike Force Alistair.
Mr Scipione did not say why the operation was wrapping up on Tuesday, but said it was closing for 'all the right reasons'. Police Minister Michael Gallacher praised 'the incredible efforts and success' of the police and the NSW Crime Commission.
He said everyone involved in the operation had 'been relentless in smashing these criminal networks'.
'Today's result confirms that together the NSW Police Force and the Crime Commission are delivering exceptional results.'