Hillary Clinton's decision to lend $5 million of family money to her own campaign has helped to spur supporters of Barack Obama into an online fundraising frenzy that appears to have more than matched that sum in barely 24 hours.

The Obama campaign is insisting that it came out on top from Democratic primary contests in 22 states on Super Tuesday even though Mrs Clinton's supporters won the biggest prizes in New York, New Jersey and California.

But despite having a well organised and long-established campaign, Mrs Clinton has fallen behind in the funding race in the past couple of months. She collected only $12 million in donations in January compared with a record $32 million for her opponent, who attracted 170,000 new donors in a single month.

Mrs Clinton confirmed yesterday that she had been forced to dip into her own pocket to make up a funding shortfall before the Super Tuesday contests and allow her to push ahead with her advertising plans.

The announcement prompted a quick e-mail to supporters last night from David Plouffe, Mr Obama's campaign manager, who said that even the team had to match the Clinton loan.

"The Clinton infusion of $5 million – and there are reports it could end up being as much as $20 million – will give them huge resources for the next set of primaries and caucuses," Mr Plouffe wrote

“Thanks to you, we have raised more than $3 million since the polls closed on February 5. But we have no choice – we must match their $5 million right now."

The call was picked up Mr Obama's official campaign blog and reposted on dozens of other sites as donors piled in via the candidate's official website yesterday evening, boasting about how they had the power to "change the world".

This morning the counter on BarackObama.com had ticked past $6.5 million in new donations since polls closed on Tuesday, giving the Illinois Senator an unexpected boost.

At a news conference yesterday, Mrs Clinton said that she had dipped into her own pocket because "I believe very strongly in this campaign".

"We had a great month fund-raising in January, broke all our records, but my opponent was able to raise more money and we intended to be competitive – and we were – and I think the results last night proved the wisdom of my investment," she said.

Her aides admit, however, that even before last night's frenzy, she would have trouble keeping up with Mr Obama's spend for primaries and caucuses over the next week. "We will have funds to compete, but we're likely to be outspent again," her chief strategist, Mark Penn, told reporters.

The Clinton’s financial disclosures reveal only broad ranges of assets but place their wealth between $10 million to $50 million – including the $5 million lent to her campaign fund.

The funding problems could hardly have come at a worst time for her campaign, given that the next few contests are expected to favour her opponent, giving him invaluable momentum as the contest moves towards the final straight.

On Saturday, the two candidates will compete in Louisiana and Nebraska primaries and a caucus in Washington. Next Tuesday there are primaries in Virginia, Maryland and the District of Columbia.

The Clinton campaign is counting on a strong showing in Ohio and Texas and the April 22 primary in Pennsylvania but risks being outspent even in those states if Mr Obama continues to attract donors.

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