Three people are expected to be charged after protesters dressed in hazmat suits stopped traffic as part of a disruptive anti-nuclear demonstration.
Orange smoke filled Collins Street in Melbourne's CBD as activists lit flares and parked a car on tram tracks outside the headquarters of major mining company BHP on Wednesday morning.
It disrupted traffic while trams on the thoroughfare were suspended for about two hours.
Victoria Police said officers removed approximately 20 people who were involved from the road.
Three people inside the vehicle were expected to be charged with public nuisance, obstructing a roadway and failing to obey a direction of a police officer.
They are a Tasmanian man, 68, a Preston woman, 32, and a 40-year-old man of no fixed address.
A Collingwood woman, 45, was expected to receive a penalty notice for lighting a flare.
Activists said the 68-year-old had secured himself to the steering wheel with a bike lock.
The protest was part of wider demonstrations linked to the Fukushima National Day of Action, marking the 14th anniversary of the nuclear disaster in Japan.
BHP is involved in uranium mining and owns Olympic Dam north of Adelaide, which it says is one the "most significant" deposits of copper, gold and uranium in the world.
Nuclear power has become a hot topic leading into the upcoming federal election, with the Liberal Party pushing for nuclear reactors to power Australia while Labor remains opposed.
