The man from Gladstone Park, north of Melbourne, was charged by police with a range of offences after it was alleged he supplied a firearm used in the attack which left 36-year-old Kai Hao dead.
Charges also include possessing cartridge ammunition without a licence or permit, committing an indictable offence while on bail and being the unlicensed dealer of a Category A firearm.
More than 150 police officers were involved in last week's counter terror operation which saw warrants executed at Ascot Vale, Glenroy and Gladstone Park.
The 25-year-old will appear at the Melbourne Magistrate's Court on 14 June.
A 32-year-old Glenroy man who was arrested during Friday's raids and interviewed by police for aiding and abetting the commission and engagement of a terrorist act, was later released without charge, the ABC reported.
A 30-year-old from Ascot Vale was also arrested and charged with numerous offences including prohibited person in possession of firearm and committing an indictable offence while on bail, Victoria police said.
Police previously confirmed that lone gunman Yacqub Khayre, 29, had two firearms during last week's siege, including a sawn-off shotgun used to fire at officers, Nine News reported.
Khayre was shot dead by police after a two-hour long hostage situation where a 36-year-old Colombian escort he had hired was held captive and tied up for a short period of time.
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