Melton Crime Investigation Unit detectives are investigating a suspicious grass fire in Strathtulloh on Saturday.
Emergency services responded to the blaze at a nature reserve on Basildon Crescent about 7.30pm.
Upon arrival, officers spotted a man on a green bike watching the fire but when they asked for his details, he fled the scene.
The fire threatened nearby properties and burned through a hectare of bushland before it was brought under control.
Police will investigate and take action to catch those responsible when a fire is deemed suspicious, whether it was a deliberate or reckless action.
Anyone found guilty of recklessly or intentionally causing a bushfire faces a penalty of up to 15 years imprisonment.
Lighting a fire on a total fire ban day can attract a fine of up to $46,000 or up to two years in jail.
Detectives have released an image of a man they believe may be able to assist with their enquiries.
He is perceived as being Caucasian in appearance, with an average build and in his mid to late 20's.
He was seen wearing tan-coloured pants, a white t-shirt and a black bucket hat, riding a green bicycle with black handlebars.
Anyone who witnesses suspicious or reckless behaviour as it is occurring should call Triple Zero (000) and anyone with other information relating to these incidents should contact Crime Stoppers on 1800 333 000 or www.crimestoppers.com.au
