Melbourne's night clubs, bars and adult-entertainment venues and their owners have been rocked by 34 firebombings, home invasions, kidnappings and shootings since April 9.
Police have laid more than 140 charges against 35 people in connection to the incidents.
The motives behind the attacks are not yet clear, but police say young people are being recruited by criminal networks to carry them out.
"Most of the arrests relate to the young people that have been tasked and caught either in the act or in preparation," Victoria Police chief commissioner Mike Bush told reporters on Wednesday.
"Some of these young people are not known to us, which is a little bit unusual," Mr Bush said.
Police established Operation Eclipse in April to target the organised crime groups behind the attacks and figure out their motivations.
Theories under investigation include extortion, disputes over illicit alcohol supply, control of security operations, and links to drug trafficking, Mr Bush said.
There had been no consistent or explicit demands made to venues, although some general threats had been reported, he said.
Investigators are working to identify who is orchestrating the campaign and how recruits are being contacted.
''What we must find out is who is orchestrating this crime scourge - who is behind this, who is pulling the strings,'' Mr Bush said.
He also warned those carrying out the attacks were putting themselves at serious risk.
''A lot of these young people, this is not what they normally do,'' Mr Bush said.
''They're putting themselves in grave danger.''
Residents near busy nightlife strips have raised concerns about their safety.
Detectives are investigating at least seven incidents in May alone, including two suspected attacks in the early hours of Tuesday.
Melbourne's La Di Da nightclub, at the corner of King Street and Little Bourke Street, went up in flames about 3.30am in a suspected firebombing.
No one was inside the venue at the time and officers were told a vehicle was seen leaving the premises.
Hours later, about 5.20am, a Yarraville business was targeted by a drive-by shooting.
Multiple shots were fired from a vehicle on Thomas Street and no one was physically injured.
Detectives from Operation Eclipse are investigating both incidents to determine whether they are linked to the broader attacks.
Victoria Police is working with Australian Federal Police, the Australian Border Force and Commonwealth partners, Mr Bush said.
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