US President Joe Biden speaks about coronavirus protections in schools during a visit to Brookland Middle School in Washington, DC, September 10, 2021. Photo: AFP

 President Joe Biden hit the hustings in California on Monday, warning voters they risk a Donald Trump-style governor if they vote to recall the state's leader.

The world's fifth biggest economy is coming to the end of a $280 million ballot on kicking the Democratic Party incumbent out of office, in an initiative sparked by Republicans angry over mask mandates and COVID-19 lockdowns.

"You either keep Gavin Newsom as your governor or you get Donald Trump," Biden told an audience in Long Beach.

"Voting no will be protecting California from Trump," Biden said. 

Newsom's main challenger is Larry Elder, a right-wing talk radio star who has openly supported the controversial former president - a figure widely loathed in California.

The black ex-lawyer is polling atop a field of 46 challengers, which also includes a cannabis consultant, a former San Diego mayor, and a self-proclaimed "Billboard Queen." 

Voters have until Tuesday evening to return a ballot on which they are being asked firstly if they should fire Newsom, and secondly who should replace him.

Newsom needs a simple majority to keep his job, and render the ballot's second part irrelevant. But should a plurality vote to dump him, then whoever polls the highest - no matter how small their majority - becomes governor for the term's remaining 16 months.

The recall is only the second in California's history; the first brought actor Arnold Schwarzenegger to office in 2003. 

Republicans, who have not had control of the famously liberal state since Arnie left office, were angered by Newsom's lockdown rules they say unnecessarily kept children out of school and suffocated small businesses as the coronavirus killed thousands in the state.