About 500 firefighters gathered to fight the blaze as Spanish Prime Minister Jose Luis Rodriguez Zapatero was said to be making his way to the island, The Times of London reported.
Planes were being used to pour water on the flames, which had destroyed up to 4,950 acres of pine forest on La Palma after being fanned by strong winds, Guadalupe Gonzalez Tano, president of the local authority, told the newspaper.
Francisco Javier Gonzalez, the mayor of Mazo, Canary Islands, told reporters more than 4,000 people had been evacuated as the out-of control wildfire neared his city.
La Palma is the fifth-largest of the seven Canary Islands and has a population of 85,000. The Times said the island is a popular tourist spot and undeveloped when compared with neighboring islands such as Gran Canaria and Tenerife.