In the draft motion, the party accused Mugabe of being a "source of instability", flouting the rule of law and presiding over an "unprecedented economic tailspin" in the past 15 years.
It also said he had abused his constitutional mandate to favour his unpopular wife Grace, 52, whose tilt at power triggered the backlash from the army that brought tanks onto the streets of the capital last week. Mnangagwa's removal was meant to boost her chances of succeeding her husband.
Mugabe's demise, now apparently inevitable, is likely to send shock waves across Africa. Entrenched strongmen, from Uganda's Yoweri Museveni to Democratic Republic of Congo's Joseph Kabila, face mounting pressure to step aside.
Mugabe was once admired as the "Thinking Man's Guerilla", a world away from his image in his latter years as a dictator who proudly declared he held a "degree in violence".
As the economy crumbled and opposition to his rule grew in the late 1990s, Mugabe tightened his grip in the southern African country of 16 million, seizing white-owned farms, unleashing security forces to crush dissent and speaking of ruling until he was 100.
Zanu-PF's action follows a weekend of high drama in Harare that culminated in reports Mugabe had agreed to stand down - only for him to dash the hopes of his countrymen in a bizarre national address yesterday.
- Reuters, AAP
How it has unfolded
Nov. 6 local time: After a campaign of public insults against Vice-President Emmerson Mnangagwa, Mugabe fires his longtime deputy, later accusing him of plotting to take power via witchcraft. Mnangagwa flees the country.
Nov 13: Army commander Constantino Chiwenga issues a rare public rebuke, saying the military won't hesitate to "step in" to calm political tensions and criticising the handling of the once-prosperous southern African nation's crumbling economy.
Nov. 14: Armoured personnel carriers are seen on the outskirts of the capital, Harare. The military moves in overnight, taking control of the state-run broadcaster.
Nov. 15: The military announces that Mugabe is under house arrest and an operation has begun to arrest "criminals" around him who harmed the economy. Unpopular first lady Grace Mugabe, who many feared would replace Mnangagwa and even succeed her husband, disappears from view.
Nov. 16: State-run media publish extraordinary photos of a smiling Mugabe shaking hands with the army commander at the State House amid negotiations on the President's exit as the military tries to avoid accusations of a coup.
Nov. 17: The army, which continues to refer to Mugabe as President, allows him to make his first public appearance since house arrest. He appears at a graduation ceremony to polite applause.
Nov. 18: The bulk of the capital's roughly 1.6 million people pour into the streets in an anti-Mugabe demonstration that even days ago would have brought a police crackdown.
Nov. 19: The ruling party Central Committee expels Mugabe as party leader and tells him to step aside as President by today or face impeachment. In a speech on national television, he does not announce his resignation as expected.
Nov. 20: The ruling party's Central Committee says it will begin impeachment proceedings when Parliament resumes tomorrow NZT, while Mugabe calls a Cabinet meeting for the same day. The military says Mugabe and Mnangagwa have made contact and will talk when the fired deputy returns to Zimbabwe "shortly."
-AP
