Lusaka - A leading contender for the Zambian presidency has refuted allegations of inciting violence as campaigning in the race to lead the copper-rich nation drew to a close Wednesday with large rallies in the capital Lusaka.

Patriotic Front (PF) party leader Michael Sata said accusations from the ruling Movement for Multi Party Democracy (MMD) that he was stoking turmoil were unfounded, while refusing to commit to accepting the outcome of Thursday's election.

Sata, who was defeated in 2001 and 2006 presidential polls, is running against MMD candidate a former vice-president Rupiah Banda, who took over as Zambian when Levy Mwanawasa died in August of a stroke.

Two other parties are also fielding candidates but the election is seen as a tight two-horse race.

Both Sata and Banda were holding final campaign rallies Wednesday in different parts of the capital.

Opinion polls carried out by two polling companies - one with close ties to the MMD - showed Sata leading Banda, who has campaigned on a theme of continuity with the popular Mwanawasa's prudent policies by several points.

In response, the MMD released its own opinion poll through state-owned newspapers Wednesday, showing Banda leading the pack with between 42 and 46 per cent against between 31 and 35 per cent for Sata.

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 Electoral Commission of Zambia (ECZ) handles the results.

On Tuesday, police in the tourist capital Livingstone fired tear gas to disperse angry opposition PF supporters, who suspected that two trucks arriving from South Africa through the Zimbabwe-Zambia border were carrying pre-marked ballot papers.

A group of people blocked the main road to the border with drums, stones and logs to prevent the trucks passing and stoned the offices of the Zambia Revenue Authority for refusing to scan the trucks, local Radio Phoenix reported..

ECZ spokesman Chris Akufuna said the two trucks were carrying lamps and batteries to be distributed to polling stations.

The opposition is distrustful of the MMD since election agents assigned to monitor the elections intercepted a government-registered van last month, which was trying to illegally ferry unverified presidential ballot papers to a remote district in southern province. (dpa)