Harare/Johannesburg  - Zimbabwe's opposition Movement for Democratic Change (MDC) leader Morgan Tsvangirai, 56, will not return Monday to Zimbabwe to begin campaigning in a run-off presidential election as expected, his spokesman said.

Tsvangirai's spokesman George Sibotshiwe said the MDC leader, who announced Saturday he would contest a presidential run-off against President Robert Mugabe, would return to Zimbabwe "within the next few days ... not today."

Tsvangirai on Saturday said he would return to Zimbabwe within two days to begin campaigning for a second round of voting in the March election, which the MDC is demanding be held by May 23, among other conditions.

Mugabe, 84, who has ruled Zimbabwe since independence in 1980, is seeking a sixth term in power, despite presiding over his country's economic ruin.

The MDC had initially resisted a run-off, saying their man beat Mugabe outright in the first round on March 29.

Official results however gave him 47.9 per cent against 43.2 per cent for Mugabe - below the 50-per-cent-plus-one-ballot threshold needed for a direct victory.

Ahead of his return Tsvangirai met over the weekend with Angolan President Eduardo dos Santos, a close ally of Mugabe, from whom he sought assurances on his safety in Zimbabwe.

Dos Santos heads the political, defence and security committee of the 14-country Southern African Development Community, which is mediating in the Zimbabwean impasse.

Asked whether the MDC leader had obtained the necessary security guarantees, Sibotshiwe told Deutsche Presse-Agentur dpa: "They (SADC) are working on it."

Tsvangirai has been based in South Africa and Botswana for the past month, amid concerns for his safety in Zimbabwe, where the MDC says over 30 of its members have been killed and hundreds of supporters injured by pro-Mugabe militia and soldiers since the elections.

Ahead of his return, Mugabe's party and the Zimbabwe Electoral Commission poured cold water on some of the conditions the MDC leader demanded for a run-off.

ZEC was quoted in a Sunday paper in Zimbabwe as saying it would "likely" not hold the run-off within three weeks of the results being announced on May 2.

Patrick Chinamasa, Mugabe's reappointed justice minister, also ruled out allowing United Nations observers in to monitor the poll and rejected the MDC's call for the state-controlled ZEC to be reconstituted. (dpa)