Cooler weather on Tuesday boosted efforts by firefighters to contain major blazes in south-central Chile that have killed 20 people.

The wildfires have consumed 35,000 hectares of land in Biobio and Nuble regions, an area the size of the US city of Detroit.

Around 1,000 homes were destroyed or damaged as the fires ripped through hilltop districts in the coastal town of Penco and adjacent port of Lirquen, leaving a blackened landscape of smouldering ruins.

Tuesday brought hope of relief as temperatures plunged and mist cloaked the area near the city of Concepcion, about 500 kilometres south of the capital Santiago.

More than 3,500 firefighters have been deployed to extinguish the flames.

President Gabriel Boric said on Monday they had managed to contain some of the blazes but that new fires had broken out in the Araucania region bordering Biobio.

In Penco and Lirquen, the fires ripped tin roofs off homes, blew out windows and reduced cars to charred carcasses.

Wildfires have severely impacted south-central Chile in recent years, especially in its warmest and driest summer months of January and February.

A 2024 study led by researchers at the Santiago-based Centre for Climate and Resilience Research found climate change had "conditioned the occurrence of extreme fire seasons in south-central Chile" by contributing to a long-term drying and warming trend.

In February 2024, several fires broke out near the city of Vina del Mar, northwest of Santiago, resulting in 138 deaths, according to the public prosecutor's office. (AFP)