Lovemore Moyo of the Movement for Democratic Change got 110 votes in the 210 member assembly, giving the opposition one of the most powerful positions in Zimbabwean politics for the first time since independence in 1980.

Moyo comfortably beat a candidate put up by a breakaway opposition faction and backed by Mugabe's ZANU-PF party, a sign the veteran leader might be unable to use parliament to force his way in deadlocked power-sharing talks.

Opposition MPs broke into song after the result, mocking Mugabe's ruling ZANU-PF party as a dying party.

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

The deadlock, in spite of strong regional and international pressure for a deal, has dampened hopes of an agreement that could end the political crisis and revive the broken economy.

In Zimbabwe's hung parliament, the speaker will be able to take charge of controversial debates if there is no power-sharing deal. The speaker can also act as president in the absence of the vice president or Senate president.

Rural Housing Minister Emmerson Mnangagwa, long seen as Mugabe's preferred successor, congratulated the new speaker.

"Mr. Speaker, Sir. This is a truly historic event and I would like, on behalf of the president, our party and this side of this august House, to congratulate you," Mnangagwa said in parliament.

Analysts said the opposition's victory in the secret vote meant that either some members of ZANU-PF or parliamentarians from Arthur Mutambara's breakaway opposition faction were ready to support Tsvangirai.

TALKS THREAT

Official sources in ZANU-PF say ruling party legislators had been ordered to vote for Mutambara's candidate after ZANU-PF decided not to contest the election.

The arrest of two opposition members of parliament before the swearing-in ceremony on Monday and Mugabe's unilateral appointment of senators were branded a further threat to talks by the opposition.

"Clearly they have chosen the path of arrogance, unilateralism that's a serious blow to confidence building in the talks," MDC spokesman Nelson Chamisa said.

One of the parliamentarians, Shuwa Mudiwa, was later released and sworn in, a Reuters reporter said.

There was no immediate comment from police on the arrests. Soon after the March elections, police announced a manhunt for several MDC politicians over charges of murder, rape and electoral violence.

Mugabe's party lost control of parliament in March elections for the first time since independence from Britain, gaining 99 seats, but Tsvangirai's party only got 100 seats so does not have an absolute majority either.

That leaves control in the hands of Mutambara's breakaway wing of the MDC, which has 10 seats. There is one independent.

Mugabe intends to officially open parliament on Tuesday despite protests by Tsvangirai's party, which says this would scuttle negotiations on forming a unity government. Tsvangirai's party did not object to the swearing-in.