SAN FRANCISCO (Reuters):

Support for Democratic presidential front-runner Hillary Clinton has fallen sharply since the summer in California, the biggest prize of all the primaries rivals have not yet benefited, a new poll released yesterday found.

The Field poll showed 36 per cent of likely California Democratic voters in the February 5 presidential primary backing Clinton, down from 49 per cent in August.

Illinois Senator Barack Obama ran second with 22 per cent, up from 19 per cent in August. Former North Carolina Sen. John Edwards was third with 13 per cent in the survey which had a sampling error of plus or minus 4.7 percentage points. No other candidate had more than 3 per cent.

Most of those who defected from Clinton appear to have landed for now in the 'undecided' column, which grew from 12 per cent in August to 20 per cent now.

"The growth in the undecideds is fairly unusual," said Mark DiCamillo, director of the Field poll. "Clinton has been on the defensive over the past month or so compared to her standing earlier in the campaign, and it has appeared to have weakened her support."

Super Tuesday

California, the most populous state, will select about a fifth of the delegates needed at the Democratic National Convention next summer, where the party's presidential nominee will be elected.

Almost half the delegates will be selected on 'Super Tuesday' on February 5 when California and 21 other states hold their primaries. Mail balloting, which could account for up to half the votes, starts in California on January 7.

Steve Westly, the former California state controller who co-chairs Obama's state campaign, said the poll showed the race was wide open.

"I don't think people here in earnest will focus until Iowa and New Hampshire," he said, referring to the January 3 Iowa caucuses and the January 8 New Hampshire primary, the first contests of the election season.

"Somewhere about mid-January you will see people focus in. That's when the campaign will start in earnest; you'll see the senator here a lot."

Many voters in Iowa and New Hampshire have a chance to see and often meet the Democratic and Republican candidates. Not so in California, where candidates more often come to raise funds in one of the wealthiest parts of the country, and rely on media coverage and commercials to reach voters.