Two other candidates have also expressed interest in contesting the vote after the death earlier this month of President Levy Mwanawasa, a senior official from Zambia's ruling Movement for Multi-Party Democracy (MMD) said.

Mwanawasa was a favourite of donor countries for tackling corruption and turning the southern African nation into one of the continent's economic success stories. He had led Zambia, Africa's biggest copper producer, since 2001, winning re-election in 2006.

Banda is acting president until new elections are called.

Banda was due to file his application later on Tuesday, the official said. Zambia's Post newspaper reported that Magande had already submitted his on Monday.

"With my rich experience in managing state operations both internationally and locally, I consider myself eminently qualified to represent the MMD party in the forthcoming presidential by-elections," the Post quoted Magande's letter to MMD party national secretary Katele Kalumba as saying.

The ruling party initially set a deadline of Tuesday for candidates to submit applications but this has been extended to Friday.

The MMD will choose its presidential candidate on September 5 to replace Mwanawasa, who died in France on August 19, after suffering his second stroke in late June. He will be buried on September 3.

Magande was not immediately available for comment.

"The secretariat is aware that his honour the vice president (Banda) and now acting president and two others plans to file their applications today," the MMD official said, speaking on condition of anonymity.

Under Zambia's constitution, an election must be called within 90 days of the presidential office becoming vacant.

The presidential term is five years, but the next president will complete the remainder of Mwanawasa's term before seeking re-election for another five years in 2011.