Speaking at a news conference she said: “Any government that goes out and assaults its people, its citizens, it has lost completely any kind of legitimacy.” Her statement comes in the wake of activists’ hunger strike to pressure Mugabe and the SADC regional body.

Zimbabwe is facing a humanitarian catastrophe as President Robert Mugabe and the opposition wrangle over a stalled power-sharing deal. Rights groups say scores of opposition activists have been murdered, tortured and beaten, Reuters reported.

Machel called on Mugabe to step down to save ailing Zimbabwe from further plunge adding: “The people of Zimbabwe have already said so ... the ballot has spoken.”

Mugabe is a veteran Zimbabwean ruler, who has been in power since independence in 1980.

The Mozambican-born Machel joined a growing list of prominent Africans who in the past year have criticized Mugabe's authoritarian rule or called for the removal of his government.

Mugabe lost the first round of a presidential election last year to MDC leader Morgan Tsvangirai, but he won the second round overwhelmingly after Tsvangirai pulled out of the race, citing violence against his supporters.

For almost a decade South Africa and other nations in SADC (Southern African Development Community) have used quiet diplomacy to try to nudge Mugabe toward democratic reforms and halt Zimbabwe's meltdown.

An apparent breakthrough was reached last September when Mugabe and Tsvangirai agreed to form a unity government, but the deal has unravelled over control of key ministries and many doubt it can be salvaged.