Four fire engines and around 25 firefighters were called to a grass fire on Stadium Road in Woolwich.
Two separate areas of grassland were damaged by the fire. There were no reports of any injuries.
A London Fire Brigade spokesperson said: “Whilst we have seen some rainfall, we’re asking Londoners not to be complacent. When the ground is very dry it’s harder for water to be absorbed, which is why we have seen flash flooding as the water pools on the surface, but it also means that grasslands are still parched and the smallest of sparks could cause a fire.
“Please continue to help us prevent grass fires by not barbecuing on open land, clearing away rubbish and glass and safely disposing of cigarettes.”
The Brigade's 999 Control Officers took 12 calls to the blaze.
The Brigade was called at 0947 and the fire was under control by 1046. Fire crews from East Greenwich, Plumstead, Eltham and Greenwich fire stations were at the scene.