Workers in surrounding office buildings were unable to leave after police inspected a white hatchback on Collins Street just after midday.
Police including the bomb squad were called to the scene and a man was quickly arrested.
The man will be interviewed regarding “an ongoing Arson and Explosives Squad investigation”.
”The matter is not terror-related and there is no immediate threat to community safety,” police said.
“The Bomb Response Unit has deployed to conduct a safety check on a vehicle in Collins Street.”
Collins Street has since reopened.
