80 firefighters are trying to settle the blaze.
30 people were evacuated at around 6:40am.
At this point, there have been no injuries.
MFB has released a 'watch and act' message for Campbellfield, Coolaroo and Somerton.
People who live in Broadmeadows, Pascoe Vale, Coburg have been asked to remain indoors.
They've been told to bring all pets inside.
The cause of the fire is being investigated.
Environment Protection Authority (EPA) staff are at the scene, helping with possible air monitoring in the area.
Bureau of Meteorology senior forecaster Michael Efrom said, “We’re looking west from Docklands and we can see it (the smoke) as well out the window.”
“At the moment the atmospheric conditions are such that the smoke is trapped in the low levels of the atmosphere. But in the morning with the temperatures going up we will see that smoke ... disperse,” he said.