"If there are continued problems over the presidency, then we go for national elections supervised by the international community," he told thousands of supporters at a rally marking the ninth anniversary of his Movement for Democratic Change (MDC) party.

Talks between President Robert Mugabe and Tsvangirai, whose MDC holds a parliamentary majority, were deadlocked in mid-August over Mugabe's desire to retain control of the security forces, according to the opposition.

The talks are being brokered by South African President Thabo Mbeki on behalf of the Southern African Development Community (SADC).

Mbeki is expected in Harare this week to revive the talks after Mugabe threatened to form a cabinet if Tsvangirai delayed signing a document to pave way for the power-sharing deal.

Tsvangirai reiterated at the rally that he would not sign up to power-sharing with Mugabe unless he was given "sufficient" powers.

"Mugabe should be head of state and I head of government," he said.

"If he does not accept that, let it be. We have time on our hands and we have the people on our side... We would rather have no deal than a bad deal."

Speaking at the same rally, the MDC's second in command, Tendai Biti, recalled that the talks had stalled over powers invested in the president by the current constitution.

"The president created in this constitution is a monarch, an imperial president," said Biti, the MDC's secretary-general.

"That's the sticking point," he said. "It's the issue of the powers of the president as enshrined in this constitution that is making these talks not to move forward."

"We are in God's hands, but we will not let the people of Zimbabwe down."

A protracted power struggle between iron-fisted Mugabe and the opposition -- which shows few signs of being resolved after the president's widely condemned one-man re-election in June -- has added to the country's woes.