But heckling by parliamentarians from the main opposition party drowned out Mugabe's speech, underscoring the bitterness of the divide.

"Landmark agreements have been concluded, with every expectation that everyone will sign up," said Mugabe, 84, who has ruled Zimbabwe with his ZANU-PF party since independence from Britain in 1980.

But parliamentarians from the opposition Movement for Democratic Change chanted "ZANU is rotten!" and "We have a pact with the people."

The MDC said Mugabe had no right to open the chamber and warned that the move would endanger the deadlocked negotiations.

But the party's parliamentarians nonetheless attended the opening of parliament, backing the MDC official who was elected to the powerful Speaker position on Monday.

ZANU-PF also holds a key post as head of the Senate, intensifying a power struggle as the two parties come under mounting pressure to reach a breakthrough that could allow them to deal with Zimbabwe's growing economic catastrophe.

ZANU-PF won a vote for the presidency of the upper house of parliament, the Senate -- where it has a majority -- meaning it can block legislation passed by parliament.

Negotiations between ZANU-PF and the MDC have stalled over what the opposition says is Mugabe's refusal to give up executive power after 28 years in office.