The "Madre Fire" broke out on Wednesday in San Luis Obispo, a rural county in the heart of the US state.

Around 200 people were ordered to evacuate, with dozens of buildings threatened by the flames.

The fire has engulfed 70,800 acres (28,700 hectares) since Wednesday, and more than 600 personnel and 40 fire engines have been deployed to contain it, Cal Fire, the state's fire service, said in an update on Friday.

It is the largest blaze so far this year in California, which was scarred by wildfires that destroyed swaths of Los Angeles at the start of the year.

This summer is the first since President Donald Trump announced plans to gut federal agencies tasked with fighting climate disaster.

On Friday, California Governor Gavin Newsom said 15 new fires had ignited on federal land in the past 24 hours, and called on the president to prioritize funding for firefighting resources.

"Trump needs to WAKE UP and start funding federal firefighters and land-management teams in these rural communities -- instead of giving tax cuts to billionaires," Newsom, a Democrat, wrote on X.

"Trump's incompetence is endangering lives."

A separate statement from the governor's press office said Friday that the Madre Fire "remains in a very isolated location -- away from homes."

It comes after several other blazes, raising fears of a difficult summer ahead for the state already traumatized by the wildfires that killed 30 people in January.

Southern California had an unusually dry winter and spring, and vegetation is already parched, UCLA extreme climate events specialist Daniel Swain has said.

Intense and widespread heat this summer, and dry brush "will heavily factor into burning conditions later this season," he added.

Since returning to the White House in January, Trump has ordered budget and personnel cuts at the Forest Service, the National Oceanic and Atmospheric Administration (NOAA) and FEMA, the federal agency that coordinates disaster response.

On Wednesday, Newsom accused the Republican president of not funding enough wildfire prevention projects.

"We need an equivalent commitment of resources -- not rhetoric," Newsom told reporters, noting that more than half of the land in California is under federal jurisdiction.