Four men allegedly involved in a dial-a-dealer syndicate which supplied more than half a million dollars worth of cocaine across Sydney will remain behind bars after they were formally refused bail in court today.

The men were taken into custody and charged on Monday after police raided seven properties in Bankstown, Croydon Park, Yagoona, Potts Hill and Condell Park, seizing nearly 1.6kg of cocaine with an estimated street value of $600,000.

Detectives also seized more than $40,000 cash, mobile phones, ammunition, firearm parts, documentation and equipment used in the supply of prohibited drugs.