Emergency services were called to a rubbish fire at Cobram Regional Park at the end of Wondah St, Cobram, on the afternoon of Monday, October 14.
Margaret Stewart was driving past the site on her way to the beach when she spotted the flames rising from a depression in the ground.
Thinking quickly, Ms Stewart shovelled dirt on to the flames, containing the fire, before calling emergency services around 2.50pm.
The Cobram branch of the CFA arrived around 3.15pm and quickly extinguished the flames.
The remains of a mattress, several glass bottles and a billy can were found within the pit.
The cause of the fire has not been established.
Cobram Regional Park is a well-frequented camping site along the banks of the Murray River.