Eight fire engines and around 60 firefighters dealt with a grass fire at Woolwich Common.
Grass the size of two football pitches was damaged by fire. There were no reports of any injuries.
A London Fire Brigade spokesperson said: “Many grass fires are avoidable with the most common causes being carelessly discarded cigarettes and matches, unattended barbecues and glass bottles that have been left on dry grass.
"We’re also concerned that some grass fires are being started deliberately and are asking parents to talk to their children about the dangers of starting fires.”
The Brigade was called at 1658 and the fire was under control by 2001. Fire crews from Lee Green and surrounding fire stations were at the scene.