WASHINGTON - John Edwards, a former Democratic hopeful for US president in 2008, has asked a federal court to dismiss charges that he used illegal campaign funds to help cover up an extramarital affair during his presidential campaign, his lawyers said on Tuesday.

Edwards, a former North Carolina senator and John Kerry's vice presidential running mate, was indicted in June on six counts, including conspiracy, accepting nearly $1 million dollars in illegal campaign contributions and making false statements.

Edwards' attorneys filed five motions to dismiss the charges that were brought against him in US District Court in Winston-Salem.

"The motions filed today demonstrate that the indictment should never have been brought in the first place and now should be dismissed by the Court," his attorneys said in a statement.

"This case is about politics," the lawyers said in one of the motions.

"In this prosecution, a major figure in the Democratic Party had been brought down and, as it turns out, a Republican US Attorney with political ambitions of his own has used this high-profile case to his personal benefit," they wrote.

The indictment accused Edwards of secretly accepting $900,000 to help cover up his affair with a campaign worker, Rielle Hunter, knowing that revelations of the liaison and her pregnancy would destroy his 2008 presidential bid.

Edwards at first denied on national television that he had the affair or paid Hunter any money. He finally admitted to the relationship, which ran from February 2006 until August 2008, and to fathering the child, which lead his wife Elizabeth to leave him. She died of cancer last year.

Edwards, a former trial attorney pleaded not guilty. If convicted, each count carries a sentence of up to five years in prison and a $250,000 fine.