Zimbabwean opposition leader Morgan Tsvangirai asked a summit of southern African leaders yesterday to set a deadline for an agreement on forming a Cabinet to end a deadlock threatening a power-sharing deal.

In a speech to regional heads of state, Mr Tsvangirai suggested his Movement for Democratic Change (MDC) would only accept a comprehensive agreement that gives his party a fair share of powerful ministries.

"Only a genuine power-sharing arrangement will allow the MDC to join a new government because that is our mandate from the people of Zimbabwe and we cannot and will not betray their hopes and dreams for a better future," he said in the speech.

One of Mr Tsvangirai's demands to the summit was "imposing a deadline on the agreement" for formation of a new Cabinet.

Mr Tsvangirai and President Robert Mugabe have been deadlocked over allocation of important Cabinet positions since the September 15 deal, which Zimbabweans hoped would produce a united leadership to revive the ruined economy in the country where inflation is the world's highest and malnutrition widespread.

The 15-nation Southern African Development Community (SADC), meeting in Johannesburg, is trying to end the impasse.

Highlighting growing regional impatience, South African President Kgalema Motlanthe said the deal offered the only hope for Zimbabwe to ease the economic crisis.

Past SADC meetings have failed to produce a breakthrough.

Although some leaders have taken a tough line on Mr Mugabe, political analysts say the SADC did not have the resolve to impose tough measures, such as sanctions, to force an agreement.

"The people of Zimbabwe are suffering and they need immediate salvation. Frustration and anger is setting in and I hope and trust that the leadership in this room will be equal to the task that history has imposed on you," Mr Tsvangirai said in the speech.

Mr Tsvangirai was grim-faced and refused to talk to reporters.