Arnold Schwarzenegger, 56, was on Monday morning (local time) sworn in as the 38th governor of California.

Schwarzenegger, a Republican, took office nearly six weeks after voters recalled Democrat Gray Davis.

California Supreme Court Chief Justice Ronald George administered the oath of office, as Schwarzenegger stood with his hand on a Bible that reportedly dated to 1811.

After the swearing-in ceremony, he asked Californians to "put the rancour of the past behind us and do the extraordinary".

"I did not seek this office to do things the way they've always been done," Schwarzenegger said in his inaugural address. "What I care about is restoring new confidence in your government."

"We spent ourselves into the largest budget deficit in the nation," he said. "We have the worst credit rating in the nation. We have the highest worker compensation costs in the nation."

Just hours after taking the oath of office, the governor signed an order rolling back a 300 per cent increase in state vehicle registration fees.