A spokesman for Peterlee Fire Station said a number of the blazes had been caused deliberately.
The spokesman said: “Crews have attended multiple incidents in Peterlee, Shotton Colliery and in the Horden area.
"Many of these fires have been caused deliberately and could of delayed us from attending more important incidents.
"If you have any information regarding deliberate fires in your area please call Firestoppers anonymously on 0800 169 5558."