President Barack Obama has come under fire from his critics over the attack, which left four Americans dead, and Clinton's move will be seen as an attempt to take the heat off him three weeks before he bids for re-election.
On September 11th heavily-armed militants stormed the consulate compound in Benghazi and attacked an annex housing US personnel, killing four Americans including the American ambassador to Libya, Chris Stevens.
In the immediate aftermath of the deaths, US administration officials said that it appeared to be linked to protests in the Muslim world against a film shot by US-based activists deemed insulting to the Islamic faith.
But it has since emerged that the prime suspects in the attack, now seen as a deliberate assault, are Al-Qaeda linked Islamist militants.
Obama's Republican rival in the November 6 vote, Mitt Romney, has accused the administration of giving a muddled response betraying a failed Middle East policy, and some of his supporters have gone so far as to allege a cover up.
The candidates are to meet in a crunch debate on Tuesday, and Clinton's intervention appears to have been timed to deflect attention from the White House as polling days looms and the polls show the race on a knife edge.