New York: US President Donald Trump's weekend visit to fire-ravaged California has prompted a withering barrage of ridicule and anger after he suggested the state should copy Finland in raking forest floors to prevent a repeat of wildfires that have killed at least 76.

He claimed he had received the tip from the President of Finland, Sauli Niinisto, who promptly said that he could not remember offering such advice.

"You gotta take care of the floors. You know the floors of the forest, very important," Trump said during his trip.

"I was with the President of Finland and he called it a forest nation, and they spend a lot of time on raking and cleaning and doing things and they don't have any problem."