Firefighters on Sunday battled a wildfire that broke out in the rugged mountains along Big Sur, forcing hundreds of residents on a precarious stretch of coast in the US state of California to evacuate and authorities to shut its main road.

The fire started Friday night in the Palo Colorado Canyon in Big Sur and quickly spread towards the sea, fanned by strong winds up to 80km/h (50 mph).

The blaze burned at least 6 square kilometres (2.3 square miles) of brush and redwood trees, said Cecile Juliette, a spokesperson for the California Department of Forestry and Fire Protection.

“The fire lined up with the wind and the terrain and that gave the fire a lot of energy to make a big run,” she said on Saturday.

Authorities made contact with about 500 residents, urging them to evacuate the sparsely populated area between Carmel and Big Sur. More than 250 firefighters from multiple agencies and volunteer groups, aided by water-dropping aircraft, contained about 20 percent of the blaze by Saturday evening.

“The winds have died down and that has worked in our favour,” she said.