The US Secretary of State Hillary Clinton is still saddled with $5.9 million in debts left over from her unsuccessful 2008 presidential bid, records filed with the Federal Election Commission show.

America's top diplomat has been steadily chipping away at unpaid campaign bills since suspending her White House bid in favour of her rival, Barack Obama in June, when her debt peaked at $25.2 million.

That amount included both $12 million owed to vendors and the $13.2 million she loaned her campaign from personal funds.

Clinton's campaign was unable to repay that personal loan by the time the Democratic National Convention convened in Denver, Colorado, in August, the deadline mandated by the 2002 McCain-Feingold campaign finance law.

The former New York senator has since forgiven the entire loan amount, leaving only the $5.9 million owed to vendors on the campaign's books.

Clinton and her supporters had been in a race against time to pay off as much of the debt as possible by the time of her swearing-in as the secretary of state on January 21.

As of that date, Clinton became subject to a federal law known as the Hatch Act, which prohibits federal employees from personally soliciting or accepting political contributions.

Clinton's mother, Dorothy Rodham, sent out the last of a series of e-mail fund-raising pitches January 16, specifically asking for donations to help retire the debt before her daughter took her new post, according to a report.