Ten fire engines and around 70 firefighters have been called to a grass fire on Ingrebourne Hill in Rainham.
Around ten hectares of grassland is currently alight.
Station Commander Kevin Morgan, who is at the scene, said: "Firefighters are making steady progress as they work to bring the fire under control.
"The fire is producing a significant amount of smoke, and we urge local residents to keep their windows and doors closed where possible.
"Please continue to avoid the area, particularly around Palmerston Road, where crowds have gathered. This is helping firefighters and emergency services to work safely and efficiently.
"This is expected to be a protracted incident, with crews remaining at the scene for a number of hours tonight."
Crews are using backpack blowers, which work just like leaf blowers. They allow firefighters to push flames back into already burnt areas. This is a tactic that provides a faster, more efficient attack on wildfires. Wildfire beaters are also being used. The beater is made of a long handle with a flat piece of rubber at the end. They’re used to beat the flames, which deprives them of oxygen and cools them down.
A London Fire Brigade spokesperson said: "During periods of dry and sustained extreme heat, the chance of wildfires spreading rapidly is high. The Brigade is ready and prepared to respond to all types of incidents, but we urge everyone to play their part to prevent incidents, such as wildfires, which can be time-consuming to resolve and have devastating impacts on livelihoods, occurring in the first place.
"If you’re planning to enjoy the weather over the coming days either in a park or other open spaces, please don’t take a disposable BBQ with you. They pose a significant fire risk as the heat can be retained for many hours, even after a barbecue has been put out. It’s also important to make sure that smoking materials are discarded of properly and either dispose of your rubbish in the appropriate bins or take it home with you if none are available.
“For those having a BBQ at home, avoid doing so on a balcony and ensure your BBQ is away from flammable materials like fences and sheds. You should also avoid setting up your BBQ on any decking you may have in your garden.”
The Brigade's Control Officers took the first of more than 20 calls to the fire at 1702 and sent crews from Barking, Romford, East Ham, Dagenham and surrounding fire stations to the scene.
The cause of the fire is not known at this time.