A fire tore through a Melbourne factory in the city's south-east overnight.

The blaze broke out just after 12.30am on Princes Highway in Hallam.

Images from the scene showed flames leaping metres into the air.

Multiple fire crews attended the scene, putting road closures in place.

In an online alert, Vic Emergency said there was no immediate threat to the community.

However, police told 9News the fire is being treated as suspicious.

It's understood the building is a school uniform factory.

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