WASHINGTON (AFP) - Hillary Clinton announced Wednesday she raised a record US$45 million (S$60 million) in the first quarter of her US presidential bid, putting the Democratic frontrunner in prime financial position in the opening months of her 2016 campaign.

"Here's what we know: In the first quarter of this campaign, supporters gave more than US$45 million," Clinton wrote in a tweet.

Final figures will be released once her campaign files its fund-raising report in July.

Signalling successful grassroots efforts to raise modest amounts across a broad platform of supporters, her campaign said that 91 per cent of the donations from April through June were US$100 or less.

Clinton officially launched her White House run on April 12.

In a Wednesday fund-raising e-mail, campaign manager Robby Mook described it as "a new record for this early in a campaign".

It surpasses the US$41.9 million raised by President Barack Obama in 2011 at the start of his re-election campaign, according to The Washington Post.

The donations, capped at US$2,700 per individual, are to be used in the primary race for the party's nomination.

Team Clinton had reportedly set a goal of raising US$100 million in 2015.

The new haul leaves Clinton well ahead of her rivals for the Democratic nomination, including liberal Senator Bernie Sanders, former Maryland governor Martin O'Malley and Rhode Island former governor and senator Lincoln Chafee.

Candidates are expected to file their fund-raising reports to the Federal Election Commission by July 15.

Clinton's first-out-of-the-gate money announcement signals her team's confidence in voter support as she gears up for a long-term campaign battle.