Lusaka - Despite leading in most polls, Zambia's main opposition party Saturday called for a delay in the announcement of presidential election results, citing irregularities in the handling of the results.

Given Lubinda, spokesman for the Patriotic Front (PF) called on Zambia's election commission (ECZ) to immediately stop the announcement of the election winner.

Lubinda told journalists Saturday that his party has credible information that the elections have been rigged and the opposition party will not accept the outcome.

The final vote tally is expected to be announced Saturday evening.

Lubinda alluded to several unsigned and unverified results being faxed by unknown people to the election results center. He slammed the Southern African Development Community (SADC) observer mission for declaring the election free and fair before consulting the opposition.

Earlier the SADC had said the elections were well managed and conducted in a credible, peaceful way.

John Kanene, head of SADC observer mission, cited the use of transparent ballot boxes and the professional conduct of Zambia's police in polling stations nationwide in a preliminary report.

But the mission noted with concern statements from opposition political parties saying that they would not accept the outcome of the elections if any rigging is suspected.

Also Saturday, the African Union (AU) said in a statement that the presidential elections were peaceful and voter counting and transmission were conducted in a transparent manner.

Head of the AU Observer mission Anil Gayan said polling was in conformity with the declaration of AU principles governing democratic elections in Africa.

The presidential election is to replace former president Levy Mwanawasa, who died of a stroke in August.

The southern African country is Africa's largest copper producer. However, 65 per cent of its people live on less that one dollar a day.

The election is a tight, two-horse race so far. Sata, president of the opposition PF is leading narrowly leading acting President Rupiah Banda - the candidate for the ruling Movement for Multi Party Democracy (MMD) - who ascended to the position after Mwanawasa' death.

In 2006, Sata's initial refusal to accept his defeat at the hands of Mwanawasa sparked days of rioting. This time, he has warned he will not call off his supporters if he suspects vote rigging. Political analysts say the mood will hinge on how the ECZ releases the results. (dpa)