One of the biggest blazes began overnight in Calenzana, a village near the northern coastal city of Calvi, burning nearly 1,300 hectares by Sunday afternoon.
“There's a lot of wind so we're focusing on trying to keep it from spreading,” the government's regional official Gerard Gavory told AFP.
Planes were dumping fire retardants on the area, and so far no homes or farms had been destroyed, Gavory said.
“Despite repeated warnings by the authorities, stubble burnings that got out of control, along with the very strong winds, started the fires,” Gavory said. “We had 20 break out yesterday and eight today.”
But while Calenzana Mayor Pierre Guidonia also denounced a “cowardly and criminal act,” state prosecutor Caroline Tharot said investigations into the cause of the fires were still underway.
Around 170 people were fighting blazes in northern Corsica Sunday afternoon, often on rocky terrain where fire trucks could not reach.
In the southern part of the island the biggest fire was at Tolla to the east of Ajaccio, with around 80 hectares burned, Colonel Christophe Magny of the regional fire service said.
In nearby fire Sampolo some 50 acres had burned, Magny said.
“There's scrub but also chestnut groves that have been hit, and with the steep terrain and the wind, this could be a major fire,” he said.
Corsica was largely spared by forest fires last year, following a series of fierce blazes during an exceptionally dry 2017.