RIOT police were called in to help bring down what detectives have described as a "high-level heroin syndicate" operating out of Sydney.
On Wednesday afternoon detectives from the organised crime squad found seven blocks of heroin, each weighing about 350g, at a Banksmeadow address where a transaction was allegedly in progress.
A further seven blocks were discovered in a car parked nearby.
Three men aged 32, 39 and 50 and a woman, aged 38 were arrested.
Later in the day, officers from Strike Force Ascalon, an operation targeting the commercial supply of drugs throughout Sydney, carried out eight simultaneous raids across the city.
Riot police forced entry into one home at Bonnyrigg which was reportedly "heavily fortified".
During the raids police found a total of $200,000 in cash, about 1kg of meth, half a kilogram of heroin powder, ecstasy, suspicious documents and electronic equipment.
Two more people, a 56-year-old man and a 50-year-old woman were arrested.
All six accused have been refused bail.