Hours before Christine Blasey Ford is scheduled to testify in front of the Senate Judiciary Committee that US President Donald Trump's Supreme Court nominee Brett Kavanaugh sexually assaulted her in high school, a fourth woman has come forward to the panel.

The new allegations, submitted in the form of an anonymous complaint sent to Republican Senator Cory Gardner, were discussed with Kavanaugh on a call with Senate investigators. Kavanaugh has denied the allegation in the letter during the call, the report quoted sources as saying. According to the letter, Kavanaugh in inebriated condition physically assaulted a woman he socialised with in Washington in 1998. The sender of the complaint described an evening involving her own daughter, Kavanaugh and several friends in 1998.