The death toll in wildfires sweeping California has risen to 31, with more than 200 people still unaccounted for.

Six more people were confirmed killed in the camp fire in the north of the state, taking the toll there to 29.

The fire now equals the deadliest on record in California with the 1933 Griffith Park Disaster in Los Angeles.

An estimated 250 000 people have been forced to flee their homes to avoid three major blazes in the state.

With strengthening winds threatening to spread the flames, California governor jerry brown has urged President Donald Trump to declare a major disaster, a move that would harness more federal emergency funds.