Gichugu MP Martha Karua is expected to launch her presidential bid Wednesday.
The former Justice minister is set to announce her bid to clinch the top seat come the next General Election, due in 2012, at the National Museums of Kenya, Nairobi.
Ms Karua has distinguished herself as a human rights campaigner and a vocal anti-graft crusader especially in parliamentary debates.
She carved a niche in the political scene by capturing the Juja and Makadara seats in a by-election against all odds.
Her party, Narc-Kenya, had sponsored the relatively unknown Mike Mbuvi, who floored seasoned politicians Dick Wathika and Reuben Ndolo.
In Juja, Narc-K's candidate William Kabogo floored the incumbent George Thuo, who was the joint-government chief whip.
Ms Karua has also distanced herself from ethnic political alliances and has refused to play second fiddle to Finance minister Uhuru Kenyatta in central Kenya politics. She is on record saying that the era of political dynasty is gone and Kenyans should be allowed to elect leaders based on choice.
With the launch, the Gichugu MP will become only the third woman to vie for the presidency in Kenyan history. In 1997, Water minister Charity Ngilu and environmentalist Wangari Maathai endured unsuccessful presidential bids.
She will join other candidates believed to harbour presidential ambitions including Prime Minister Raila Odinga, Vice President Kalonzo Musyoka and Mr Kenyatta.
Others in the crowded field are: Local Government minister Musalia Mudavadi, Eldoret North MP Wiilliam Ruto, MPs Eugene Wamalwa (Saboti) and Bifwoli Wakoli (Bumula)