California Democrats went to the polls to pick a candidate to challenge Governor Arnold Schwarzenegger for the leadership of the golden state after a vitriol-fueled election campaign.

California Treasurer Phil Angelides (C) walks with his wife Julie (R) and daughter Megan, to cast his vote in Sacramento, California, June 6, 2006. Voters go to the polls today to decide who will take on Governor Arnold Schwarzenegger in the upcoming November election. [Reuters]

Democrats Phil Angelides, 52, the state's treasurer, and rival Steve Westly, 49, California's financial controller, were in a statistical dead heat to become their party's candidate for governor ahead of the November 7 poll, a survey showed.

Some 15.7 million Californians are registered to vote in Tuesday's primary election, balloting for which runs from 7:00 am (1400 GMT) until 8:00 pm (0300 GMT Wednesday), but pollsters said barely one-third were expected to turn out.

Political experts warned that the mud-slinging campaign that Angelides and Westly have waged against each other ahead of the primary could ultimately end up helping Republican Schwarzenegger.

The 58-year-old former action movie star, who took power in a landslide special election in late 2003, has no Republican opponents, but he has seen his once-massive cross-party popularity decline to record lows amid a string of political setbacks.

Instead of attacking incumbent Schwarzenegger, the rival Democrats have waged vitriolic advertising campaigns against each other, with Westly accusing Angelides of polluting California's Lake Tahoe through his investment in a property development.

Angelides meanwhile accused Westly of having shady business connections.

A June 2 Field Poll showed that Westly had 35 percent support against Angelides' 34 percent, leaving a wafer-thin margin between the men.