The decline of democracy in Zimbabwe should be a lesson to other southern African leaders, Nelson Mandela's wife Graca Machel said on Wednesday.

Zimbabwe's President Robert Mugabe demonstrated how once respected liberation fighters could lose legitimacy, the former South African and Mozambican first lady said at the launch of Save Zimbabwe Now, according to AFP.

The group is set to hold a hunger strike and fast in solidarity with the desperate levels of hunger in Zimbabwe.

Any government which goes out and assaults its own people, its own citizens, it has lost completely any kind of legitimacy, Machel said.

She urged leaders to learn from the mistakes of Mugabe.

We came together to liberate ourselves but now we show that power and the way you exercise power can pervert you to become precisely the opposite of what led you to became a freedom fighter, she added.

Mugabe, 84, has ruled Zimbabwe since the end of British colonial rule in 1980 but lost to rival Morgan Tsvangirai in March polls. The troubled country is now stuck in a political deadlock with no signs of settlement in the near future.