Wade will fly to Zimbabwe for a 48-hour visit after British Prime Minister Gordon Brown said on Tuesday he would boycott the planned December 8-9 Lisbon summit because Mugabe would be there, a spokeswoman said.

"President Wade's visit is in the framework of the Lisbon summit because in order for the summit to be a success, it is necessary for everyone to be there," presidential spokeswoman Fatou Tandian told Reuters on Tuesday.

The Senegalese leader, a critic of South African efforts to resolve the political crisis in Zimbabwe, has called for an active role for other African leaders in negotiations between Mugabe and his domestic opponents. Wade had originally planned to visit Zimbabwe last month, but the trip was postponed.

A grouping of southern African nations has mandated South Africa's Thabo Mbeki to secure a deal on constitutional reform between Mugabe and the opposition Movement for Democratic Change (MDC) ahead of presidential and parliamentary polls in March.

However Wade, who has sparred with Mbeki for leadership on continental issues, said the whole of Africa shared the responsibility to prevent the collapse of Zimbabwe.

Once the bread basket of southern Africa, the country suffers chronic food and fuel shortages, 80 percent unemployment and the world's highest inflation rate, topping 8,000 percent.

Mugabe accuses the West, and particularly former colonial power Britain, of conspiring to ruin his government as revenge for Zimbabwe's seizure of white-owned farms.

Brown, a leading advocate of debt-relief to Africa, has sharply criticised Mugabe for rights abuses during his 27-year rule and said he would boycott next month's EU-Africa summit, the first in seven years, if the Zimbabwe leader attended.

The dispute raises heckles in Africa, where many still regard Mugabe as an independence hero for his part in toppling the white-minority government of Ian Smith, who died last week.

Mbeki, who praised Mugabe's support for the struggle against apartheid in South Africa, said recently he was very confident his mediation would resolve Zimbabwe's crisis. The MDC, which has accused Mugabe of intimidation and election rigging, also expressed optimism last week that the talks could succeed.

Wade's announcement of his mediation trip comes a week after Mbeki cancelled a working visit to Senegal at the last minute, citing a diary clash with a Commonwealth summit in Uganda.