Vic vitamin factory goes up in flames

A vitamin supplement warehouse in Melbourne has been hit by a suspected arson attack.

Firefighters say it's not the first time the factory has been the target of suspected arson.

Fire crews were called to the factory at Dingley Village just before 2am on Thursday, where they found a fire at the back of the premises.

The fire was brought under control quickly but crews remained at the scene for about 90 minutes.

The fire is being treated as suspicious and damage is being assessed.

Another suspicious fire reportedly broke out at the factory late last year.