The indications of a possible breakthrough came as South African Deputy President Jacob Zuma arrived in the Burundi capital in a bid to ease tensions between Burundi's bickering factions ahead of a constitutional referendum next month.

Presidential spokesman Pancrace Cimpaye said advanced contacts had taken place with Burundi's last rebel group, the National Liberation Front (FNL), in order to establish a negotiating framework, with talks expected to take place in Dar es Salaam.

Six of seven anti-government rebel movements have signed ceasefires and peace has been restored in 16 of the small country's 17 provinces.

Only the FNL, declared a "terrorist group" by the Great Lakes nations in central Africa, has continued hostilities against government forces.

Zuma, chief mediator of the country's languishing peace process, touched down here amid a fierce war of words over the possibility of amendments to the constitution that have further split the already divided nation.

Zuma "is here to address matters related to constitutional reform," an official from the South African embassy official told AFP. "He will listen to different opinions before proposing a solution."

Burundi is struggling to recover from an 11-year civil war that claimed more than 300,000 lives and Zuma arrived a day after Burundi's national election commission announced that a thrice-delayed referendum, a major part of the transition process, will be held on February 28.

President Domitien Ndayizeye, a Hutu, wants to amend the constitution to allow voters to cast ballots directly for their candidate in this year's presidential election, another key element in the process, to be held by the end of April.

That possibility has split the nation into rival camps with Ndayizeye's own party, the Burundi Democratic Front (FRODEBU), opposed as is Burundi's main former Hutu rebel group, the Forces for the Defense of Democracy (FDD).

The FDD has accused Ndayizeye of trying to indefinitely prolong the transition period and suggested he wants to remain in power permanently.

Whether or not February's referendum will contain Ndayizeye's proposed changes has been the subject of intense debate in Burundi.

Shortly after the election commission announced the new date for the referendum hundreds of demonstrators took to the streets of the capital demanding the inclusion of the modification.

But opponents have been equally vocal and, earlier this month, Burundi's constitutional court ruled that Ndayizeye had the right to put any possible change to the document to the voters through a referendum.

During his visit, Zuma is to meet Ndayizeye, his Burundian counterpart, Frederic Ngenzebuhoro, leaders of the country's political parties and the diplomatic corps.

Burundi's civil war was triggered by the assassination in October 1993 of the country's first elected Hutu president by the Tutsi-dominated army, triggering a Hutu rebellion.

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