Firefighters were battled dozens of raging wildfires in Chile while seeking to gain control of one of the country's worst natural disasters in years as the death toll rose to at least 24 with nearly 1,000 more people injured.

International help was set to arrive from a handful of countries that have pledged resources, including planes and expert firefighting teams, as the most intense wildfires torched forests and farmland clustered around three regions near the middle of the South American country's long Pacific coastline.

The government of President Gabriel Boric has issued emergency declarations for the largely rural southern regions of Biobio, Nuble and Araucania in an effort to speed relief.

The fires have consumed some 270,000 hectares, officials said. Thirteen of the dead come from Biobio, which, like Nuble and Araucania, is home to extensive forests as well as farms that grow grapes and other fruit for export.

At least 26 of the 970 injured are listed in grave condition at local hospitals.

A heat wave in the Southern Hemisphere's summer has complicated efforts to extinguish the flames, as temperatures in some of the most affected areas have exceeded 40 degrees celsius.

Pockets of intense fire could be seen coming out from the forested hills off the coast near the town of Dichato just outside the city of Concepcion in the Biobio region last night, as light from the flames illuminated boats in the small harbour.

Some 260 fires are active across the region, interior ministry officials said, with 28 of them considered especially dangerous. Nearly 1,500 people have fled to area shelters.

A burnt house is seen in Puren, Araucania region, Chile

While authorities said international assistance would soon arrive from countries including the US, Argentina, Ecuador, Brazil and Venezuela, a specialized team of personnel from Spain was en route today.

The heatwave has created fears of a repeat of 2017, when widespread fires in the same region left 11 people dead and destroyed 1,500 homes.