An investigation into Molotov cocktails being hurled into groups of homeless people in inner-Sydney has uncovered an alleged drug syndicate supplying Kings Cross.

Police arrested nine people and raided six homes in the Woolloomooloo area on Friday morning who they allege are behind the distribution of cocaine and heroin in the Kings Cross area.

Along with the five women and four men, police also allegedly uncovered an unspecified amount of cannabis and heroin. All nine were taken to Kings Cross police station and are expected to be charged.

Police said the arrests came about as part of the investigation into an incident in February where three Molotov cocktails were hurled into Tom Uren Place.