Arnold Schwarzenegger has made a rare appearance at California's Capitol Hill to unveil his official portrait.

The oversize work, painted by Austrian-Irish artist Gottfried Helnwein, is a photograph-like image of a youthful looking Schwarzenegger standing in front of the official California seal.

"When I was a young man in Austria, I dreamed about coming to California every day," said Schwarzenegger, an immigrant who eventually married into the family of the late US President John F Kennedy.

"But never in my wildest dreams did I ever think I would become governor."

The one-time bodybuilder and prolific film star took the state's helm in a chaotic recall election of 2003.

A Republican in a state known for its liberal policies, Schwarzenegger often reached across the aisle to work with Democrats.

The mortgage meltdown and recession hit toward the end of his second term, which finished in 2011.

Schwarzenegger's return to the state capital of Sacramento for the first time since leaving office drew a packed crowd.

"Never before have I seen so many people and so many cameras for a news conference," said the current governor, Democrat Jerry Brown.

"Arnold, you still have it!"

True to his outsized life, Schwarzenegger's portrait is larger than those of other modern-day governors.

Lieutenant Governor Gavin Newsom said the image was appropriate because he is "larger than life".