The fire started at about 9pm on 29 November.
A small area of grass and shrubs was burnt before the fire was put out by CFA crews. No one was injured.
Police would like to hear from two teenage boys on BMX bikes who spoke to firefighters. One of the boys is described as Caucasian, mid-teens, slim build with shoulder length dark hair. He was wearing a black hoodie, jeans and a black cap with a red peak. The other is mid-teens with blond hair.
Anyone with information should call Crime Stoppers 1800 333 000 or visit crimestoppersvic.com.au
