There were no immediate reports of human deaths or serious injuries but nearly 1500 people were evacuated across the island on Sunday, state broadcaster Rai News reported.
Firefighters said several homes were damaged in the island’s western interior region.
Civil protection authorities said a preliminary survey indicates 10,000 acres have been engulfed in flames around Montiferru, near the centre of the island.
Eleven aircraft were working to put out the flames, the head of the island’s civil protection agency, Antonio Belloi, told Italian news agency ANSA.
Two firefighting planes from France and two from Greece arrived in Italy to assist in containing the fires, Italy’s civil protection agency said.
Officials said some 7500 emergency workers, including members of Italy’s forest police and the Red Cross, were helping evacuees and those at risk.
Efforts were being hampered by hot southwesterly winds, putting the fire danger level at “extreme”.
With temperatures expected to remain high on Monday, authorities are warning residents to remain on alert until the fire is fully under control.
Christian Solinas, president of the Sardinia Region, described the fires as “an unprecedented disaster”.
He said it was not possible to determine the full extent of the damage but that he would asked Prime Minister Mario Draghi to allocate recovery fund money for reforestation projects.
