FIREFIGHTERS believe a fire at a Mildura unit on Monday was deliberately lit.

Fire Rescue Victoria responded to a structure fire at 11.41am after callers to 000 reported a fire.

Firefighters arrived on scene within seven minutes to find the fire, believed to have originated on a mattress in a bedroom.

The fire was quickly extinguished and the scene was deemed under control at 11.54am. Mildura police also attended the scene.

A spokesperson for FRV said the fire was deemed suspicious.