A fourth woman has accused Republican Presidential hopeful Herman Cain of sexual harassment.

The woman, Sharon Bialek, says she was sexually harassed by Cain after seeking his help on an employment issue while he was the head of National Restaurant Association.

She is the first person to publicly detail her claims.

At least three other women have accused the former pizza magnate of sexual harassment during the 1990s while at the NRA.

Cain has acknowledged that he was the subject of sexual harassment complaints, but has denied any wrongdoing.

The distraction comes at a critical moment for Cain's presidential campaign, which has surged in recent weeks. The former Georgia businessman is at or near the top in national polls, and holds a narrow lead in the latest poll in Iowa, the state that begins the Republican nomination process on January 3, 2012.