The fire was lit in a walkway area of the public reserve in Stokes Green at about 6pm, and burnt about 30 square metres of grass and scrub.

The CFA were called by residents to extinguish the fire, and three youths were reportedly seen running away from the scene.

Senior Sergeant Graham Higginbotham of the Pakenham police said the fire came close to the fences and gardens of homes around the reserve.

Three boys, aged 13, 10 and 10. returned to the scene later that evening.

They were questioned by police, who said the boys showed them where they discarded a cigarette lighter used to start the fire.

The three were then taken to Pakenham police station. Police said they made full admissions to the crime and were cautioned over arson-related offences.

Senior Sergeant Higginbotham said families needed to be vigilant about their children playing with fire.

"Parental monitoring and guidance of young people is vital.

"This could have very easily turned into a tragic situation, with houses nearby."

The three youths were referred to a juvenile fire awareness and intervention program run by the MFB and CFA. The state-wide program is free and confidential and involves

firefighters visiting the young person and their family in their home to teach them about fire safety and taking responsibility for their actions.

According to the program's website, the average participant is a boy aged between nine and 10 from a single-parent home with at least one smoker in the family.

Senior Sergeant Higginbotham said the program was ongoing and intensive and would go on for as long as required to change the young person's behaviour.