Almost half a kilogram of heroin was seized after police stopped a driver for a random breath test at Villawood on Thursday night.
Police from Bankstown Local Area Command stopped a 64-year-old man in Binna Burra Street bout 10.30pm, after they saw him allegedly driving erratically.
A package was found on the driver when he asked to get out of the vehicle.
During their search, police allege the package contained more than 400g of heroin.
The drugs have an estimated potential street value of more than $100,000.
The man was arrested and taken to Bankstown Police Station, where he was charged with the commercial supply of a prohibited drug (heroin; and dealing with the proceeds of crime.
He was refused bail to appear in Bankstown Local Court on Friday, October 20.