In March this year, NSW Police established Strike Force Dudi to investigate an affray involving a number of men on Elizabeth Street in Waterloo.
A number of people have since been charged and remain before the courts.
Investigators found that prohibited weapons were allegedly being sold from businesses in Haymarket.
Officers yesterday executed search warrants at businesses on Hay Street, Haymarket, and homes in Amos Street, Westmead, and Shepherd Street, Cherrybrook.
During the search, police seized more than 300 prohibited weapons, including flick knives, sheath knives, butterfly knives, zombie knives, push daggers and concealed blades.
Two men, aged 45 and 60, were arrested in Haymarket charged with multiple weapons dealing offences.
They were refused bail to appear in court today.
Inquiries under Strike Force Dudi are ongoing.