Houses burn amid the spread of wildfires in Vina del Mar, Chile, on Saturday. Reuters

Wildfires blazing across Chile have killed at least 51 people, leaving bodies in the street and homes gutted, with flames continuing to spread on Sunday and the toll expected to rise.

President Gabriel Boric has decreed a state of emergency in the central and southern parts of the country "due to catastrophe," as dry conditions and temperatures soaring to 40 degrees Celsius (104 degrees Fahrenheit) exacerbated the crisis.

Dense gray smoke blanketed the city of Vina del Mar of the Valparaiso tourist region, along central Chile's coastline, forcing residents to flee.

Rosana Avendano, a 63-year-old kitchen assistant, was away from home when the fire began to sweep through El Olivar, an area of Vina del Mar, where she lives with her husband.

"It was terrible because I couldn't get (to my house). The fire came here... we lost everything," Avendano told the media.

"My husband was lying down and began to feel the heat of the fire coming and he ran away."

Dense gray smoke blankets the city of Vina del Mar of the Valparaiso tourist region. AFP

She feared the worst for hours, but eventually was able to contact her spouse.

The death toll rose to 51 on Saturday as firefighters battled to control the flames. The forensic medical service had previously reported 45 deaths, but "there are six more people who died in health care facilities," according to interior under-secretary Manuel Monsalve.

Boric said the number of victims would increase, pledging government support to help people get back on their feet.

Authorities imposed a curfew beginning at 9pm on Saturday (0000 GMT Sunday), to allow emergency supplies -- especially fuel -- into the affected areas.

New evacuation orders were issued, though it remained unclear exactly how many people had been told to leave.

Earlier Saturday, Interior Minister Carolina Toha said there had been 92 fires as of noon, with 43,000 hectares (106,000 acres) burned across the country. Firefighters were still battling 29 of the blazes by the afternoon, while 40 had been brought under control.

In the hillsides around the coastal city of Vina del Mar, entire blocks of houses were burned out overnight, AFP reporters saw Saturday morning, as thousands of people who had previously evacuated returned to find their homes destroyed.

Aerial view of burned vehicles in the El Olivar commune after a forest fire in Vina del Mar, Chile, on Saturday. AFP

Some of the dead were seen lying on the road, covered by sheets.

The area, about 1.5 hours northwest of the capital Santiago, is a popular tourist destination during the summer months. The coastal region is also important for the country's wine, agricultural and logging industries.

In the towns of Estrella and Navidad, southwest of the capital, the fires burned nearly 30 homes, and forced evacuations near the surfing resort of Pichilemu.

"It's very distressing, because we've evacuated the house but we can't move forward," said 63-year-old Yvonne Guzman, who fled her home in Quilpue with her elderly mother, only to be trapped in traffic for hours.

"There are all these people trying to get out and who can't move," she told the media.

Vina del Mar Mayor Macarena Ripamonti said, "We're facing an unprecedented catastrophe, a situation of this magnitude has never happened in the Valparaiso region."

Agence France-Presse