The Tyne and Wear Fire and Rescue Service (TWFRS) is reminding people of the dangers from controlled burning.
It said it has seen a 115% increase in fires caused by people burning waste in their gardens since the nationwide lockdown was imposed.
During the same period in 2019 (23 March to 7 April), the service responded to 38 fires caused by controlled burning. This year it has recorded 82 callouts.
The TWFRS said these fires often spread to flammable materials which in turn cause bigger fires and environmental hazards.
Peter Heath, TWFRS assistant chief fire officer, said: "Crews are increasingly responding to garden fires, often 'bonfires' that have spread to fences, or other materials or where the fire contains items causing smoke hazardous to human health.
"These fires are a significant source of air pollution and the smoke can include poisonous gases, such as carbon monoxide.
"Our advice is very straightforward and clear - don't burn household waste, plastics, rubber or any other material, which could cause harmful smoke."
"We are also concerned that some younger people are continuing to meet up with friends and could be spreading or catching the coronavirus.
"We know that young people can have a tendency to believe themselves to be invincible, but very sadly, the coronavirus is no respecter of age."