Zimbabwe's beleaguered Vice President Joice Mujuru defended herself on Monday against allegations that she masterminded a plot to assassinate President Robert Mugabe.

Dismissing the claims as "entirely untrue", Mujuru said in a statement she was ready to defend herself against accusations of treason in a court of law.

The allegations were contained in a report in the Sunday Mail, seen to be controlled by loyalists of Emmerson Mnangagwa, a top official in the ruling Zanu-PF.

He and Mujuru lead rival factions battling to seize control of the party -- and the Zimbabwean government -- as Mugabe edges towards possible retirement.

Mugabe's wife Grace has led a campaign against Mujuru in the past two months, with the apparent backing of Mnangagwa.

Mujuru has remained silent until now, but allegations that she plotted to assassinate Mugabe had forced her to respond, she said.

"While I personally believe silence is golden... I have been obliged to make this statement for and on behalf of all current and future national leaders who may face the same problems," Mujuru, 59, said.

"I regret that certain persons have elected to make false, unsubstantiated, malicious, defamatory and irresponsible statements about me... I stand ready to defend myself before the party and in any court of law on any of the allegations made against me."

Mujuru's husband, former army general Solomon Mujuru, was killed in a house fire in 2011 that many Zimbabweans believe was part of a power struggle within Zanu-PF.