Southern African leaders on Monday condemned an army-backed takeover in Madagascar as they opened a summit to consider sanctions against the island's transitional leader Andry Rajoelina.

"This unconstitutional takeover by the de facto regime in Madagascar violates the basics principles, protocols and treaties and is unacceptable," said Swazi King Mswati III at the opening of the talks.

"We are here to deliberate on the best possible way forward to address the present situation in Madagascar."

The African Union has already suspended Madagascar over the ousting of president Marc Ravalomanana earlier this month.

Ravalomanana arrived about an hour after the summit opened to brief the leaders on the situation in his country, where he was forced out of office when the army turned against him after a bitter three-month struggle.

His supporters have taken to the streets in protest, with about 15 000 people rallying in the capital in the latest demonstration on Monday.

For Madagascar, a regional security organ currently headed by Mswati has already warned that the bloc could impose sanctions on Rajoelina's government, and sent a fact-finding mission to the vast island off Africa's east coast.

SADC's executive director Tomaz Salomao headed the mission and was set to lead deliberations on how to help Madagascar return to democracy.

But the summit's first line of business was to consider a request by Zimbabwe for billions of dollars in aid to rebuild its shattered economy.

South Africa's Foreign Minister Nkosazana Dlamini-Zuma said that Zimbabwe had put forward a plan that would require nearly 10 billion dollars.

She told reporters on the sidelines of the summit that Sadc members would take the next two weeks to consider what aid they could provide, which would be "according to our means."

Zimbabwe has sought about two billion dollars in aid and loans as a down payment on its economic recovery scheme, but so far has had little luck in swaying multilateral lenders like the International Monetary Fund or major western donors.

Sadc, which includes some of the world's poorest countries, has not yet made any specific offers other than agreeing to press the IMF and the World Bank to extend loans while urging western countries to end sanctions on Mugabe and his inner circle.

Mswati heaped praise on Zimbabwe, where long-time opposition leader Morgan Tsvangirai last month joined President Robert Mugabe in a unity government.

"We continue to be happily impressed by the progress made in the formation and operationalisation of the inclusive government," he said.

"However, the greatest challenge Zimbabwe is now facing is the recovery of their economy."

The king described the request for aid as a "most heartening and encouraging" sign of the unity government working together.

But he again called on western countries to lift sanctions against Mugabe and his inner circle, which he said were hindering the country's recovery plan.

"Unfortunately, this cannot be successfully implemented while Zimbabwe is under sanctions that continue crippling their economy," he said.

Zimbabwe's economy has been in freefall for nearly a decade, with record hyperinflation, unemployment at 94 percent and a collapse of services which resulted in a deadly cholera epidemic.

AFP