(Adds comment from election body, paragraph 15, 16)

By MacDonald Dzirutwe

HARARE, May 3 (Reuters) - Zimbabwe's main opposition party said on Saturday it was still undecided on whether its leader, Morgan Tsvangirai, should take part in a run-off election against President Robert Mugabe.

Election officials announced on Friday that Tsvangirai, who heads the Movement for Democratic Change (MDC), had beaten Mugabe in the March 29 presidential poll but failed to win the absolute majority necessary to avoid a second ballot.

The MDC has accused election officials of rigging the results, which showed Tsvangirai won 47.9 percent of the vote to Mugabe's 43.2 percent. The party says Tsvangirai won the election outright and Mugabe's rule is over.

But it has not signalled how it will handle the run-off.

"If you want a 'yes' or 'no' answer, it's not going to come (for now) because there are issues that have to be clarified," MDC spokesman Nelson Chamisa said at a news conference after the party's national executive met to discuss the run-off.

The government said it expected the MDC to take part.

"We know they are going to participate in the run-off but want to buy time because they are not ready," Deputy Information Minister Bright Matonga said.

The MDC reaffirmed its position that Tsvangirai had won the election outright and that there was no need for a run-off. It said its representatives had not been allowed to verify results.

Zimbabweans are struggling with a deep economic crisis, marked by chronic food and fuel shortages, inflation of more than 165,000 percent and rising poverty and malnutrition.

Thokozani Khupe, MDC vice-president, told reporters the party was lobbying the Southern African Development Community (SADC) to urge the Zimbabwe Electoral Commission (ZEC) and the ruling ZANU-PF party to allow the MDC to check the results.

"We are talking to SADC leaders so that they put pressure on ZEC and ZANU-PF to proceed professionally," Khupe said.

FOREIGN INTERFERENCE

The government dismissed the MDC's approach to SADC as a stalling tactic. "Lobbying SADC over a verification process they (the MDC) took part in is wasting time," said Matonga.

Mugabe, in power for 28 years, has accepted the official results and will contest the second ballot. He would stay in power under electoral laws if Tsvangirai boycotts the run-off, which by law should be held within 21 days of the first ballot's results.

ZEC has the power to extend the period in between the two ballots, and political observers say a 40-day wait was likely.

ZEC chairman George Chiweshe said the commission would meet soon to set a run-off date.

"The commission is going to meet as soon as possible. I cannot state exactly when the run-off will be held, but I can confirm that the poll will be on a date to be announced by the commission," he said in comments carried in the online addition of the state-owned Sunday Mail.

The opposition, Western governments and human rights groups have accused Mugabe of unleashing militias to scare Zimbabweans into backing him in the run-off. The government denies the allegation and says the MDC has carried out political violence.

Twenty MDC supporters have been killed and more than 1,000 homes have been burnt or destroyed by ZANU-PF militia since the elections, Khupe said. Mugabe's critics say they doubt the next ballot will be fair.

It is unclear how Western powers will react to the run-off.

On Friday, the United States and former colonial power Britain questioned the credibility of the official results.

Mugabe, regarded by many in Africa as a liberation era hero, accuses Britain of plotting with the opposition to oust him.

Few African leaders, including South African President Thabo Mbeki, have criticised the Zimbabwean leader publicly. (Additional reporting by Cris Chinaka and Nelson Banya; Writing by Paul Simao; Editing by Richard Balmforth) (For full Reuters Africa coverage and to have your say on the top issues, visit: http://africa.reuters.com/ )

AlertNet news is provided by