Tsvangirai told a news conference in Nairobi that President Robert Mugabe's intention to open parliament next Tuesday was a "repudiation" of the Memorandum of Understanding with the opposition on the framework for talks.

"A violation of the MOU will have to be dealt with by the mediator," he said. South African President Thabo Mbeki and other senior officials from his country are mediating in the talks, which began last month.

"If President Mugabe goes ahead to convene parliament, appoint a new cabinet, it means he is proceeding to violate the conditions of the MOU which means he may have abandoned the basis for the talks but we don't know what his intentions are," Tsvangirai added.

He confirmed that the power sharing talks were deadlocked over the roles of president and prime minister in a new government. Mugabe is expected to remain as president but, backed by security chiefs, he is reluctant to cede major powers. Tsvangirai wants a real executive power as prime minister.

"There is one stumbling issue which we have been grappling with -- the framework of the power and roles of the president and the new position of prime minister for the duration of the transition leading up to 2-1/2 years," Tsvangirai said.

Whereas the opposition wants a comparatively short transition before new elections, Mugabe is believed to be aiming for a full five-year term.

Mugabe's decision to forge ahead with the opening of parliament suggests there is no solution in sight to the deep deadlock with Tsvangirai's Movement for Democratic Change (MDC) and could suggest the veteran leader has abandoned negotiations.

Political analyst and Mugabe critic John Makumbe said on Wednesday Mugabe, known as a skilful negotiator, had gained the upper hand over Tsvangirai.

IMPASSE

The negotiations began last month to resolve an impasse following Mugabe's unopposed election in June in a widely condemned vote boycotted by Tsvangirai because of violence against his supporters.

Tsvangirai won the first round of presidential elections in March and says that entitles him to effective leadership of the once-prosperous nation.

Both sides are under major pressure from both within Africa and around the world to reach an agreement that will pave the way for the rebuilding of Zimbabwe's devastated economy, now suffering inflation of at least 11 million percent.

The crisis has flooded neighbouring states in the Southern African Development Community (SADC) with millions of economic refugees.

Tsvangirai said a new prime minister in Zimbabwe must have the authority to run and control government. He said he did not expect Mugabe to be a ceremonial president but neither could he be a ceremonial prime minister.

He said he had come to Kenya, for talks with Prime Minister Raila Odinga, to try to learn from the power-sharing deal that ended a bloody post-election crisis earlier this year in which an estimated 1,500 people died.

"We have this new experiment in Africa where people who loose elections want to negotiate their way back into government," he said.

Mbeki has been mediating since last year but is under increasing criticism both at home and abroad for ineffective tactics and not putting enough pressure on Mugabe to reach a deal.

In his news conference, Tsvangirai suggested Mugabe would not be able to convince all members of parliament to attend next Tuesday's opening. "President Mugabe will not proceed to do anything unilaterally, any steps that we take have to be by consensus," he said.

Tendai Biti, secretary general of the MDC said on Wednesday that opening parliament would "decapitate the dialogue" and show that Mugabe's ZANU-PF party was unwilling to continue with talks.