President Jacob Zuma's mediation trip to Libya this week will test the relevance of the increasingly discredited African Union as well as an old friendship between South Africa's governing party and strongman Moammar Gadhafi.

Zuma, who arrives Monday, will be looking to restore some faith in the 54-nation pan-African body whose diplomatic efforts to resolve Libya's crisis were sideswiped by NATO airstrikes that began March 19.

Officially, Zuma arrives in Tripoli — the capital and stronghold of Gadhafi, whose command centers have been pounded by a relentless NATO bombardment for days — to resuscitate an African roadmap drawn up in February that calls for an immediate cease-fire.

Unofficially, Zuma will try to persuade Gadhafi to step down, South Africa's influential Mail and Guardian newspaper reported, quoting a senior security source.

His visit comes as all sides appear stalemated: Gadhafi has remained intransigent in the face of stepped-up NATO airstrikes; the rebels have proved unable to capitalize on the airstrikes to advance the battle fronts and are fast running out of cash even as they win increasing diplomatic recognition.

Hundreds of thousands of Libyans are suffering: in Tripoli from the trauma of the bombings as well as growing shortages and increasing prices of fuel and food; in western mountain towns besieged by Gadhafi's forces; in refugee settlements at borders with Tunisia, Chad and Egypt.

South Africa voted for the U.N. resolution authorizing a no-fly zone over Libya and the use of force to protect civilians, using its power as a rotating member of the Security Council to flout an African Union stance demanding a peaceful resolution.

Since then, Zuma has joined other African leaders in accusing NATO of overstepping the U.N. mandate and calling for an end to the airstrikes.

Relations with Gadhafi already were strained when Zuma came to Tripoli in April at the head of an African delegation. But he came away pleased, having won Gadhafi's agreement to a cease-fire. The same day it became clear that Gadhafi was not honoring his word.

The rebels' National Transitional Council in their eastern bastion of Benghazi already had dismissed the African roadmap because it did not demand Gadhafi surrender power.

The African plan calls for an immediate cease-fire; ensuring humanitarian aid reaches all who need it; protection of foreigners, including African migrants; and "adoption and implementation of the political reforms necessary for the elimination of the causes of the current crisis."

In Benghazi on Saturday, rebel council chairman Mustafa Abdul-Jalil emphasized that any solution would have to involve Gadhafi's departure.

"We would like to reconfirm that the basis of any consideration for the resolution of the Libyan crisis, is the elimination of the main cause of this crisis, Col. Gadhafi."

The Mail and Guardian said Zuma's trip to Tripoli is at the request of the rebels, though no rebel official would confirm that.

"We welcome any political solutions that help end the bloodshed, but they must be predicated on the departure of Gadhafi, his sons and his regime," Abdul-Jalil said.

Zuma has known Gadhafi since the 1980s when he was the intelligence chief of the then-outlawed African National Congress and Gadhafi provided arms and money for its fight to end a brutal white minority regime in South Africa.

Two decades later, Nelson Mandela was able to return the favor, using his international moral standing to end Libya's pariah status. Mandela helped broker the agreement that ended sanctions imposed on Libya over the downing of a civilian jetliner that killed all passengers over Lockerbie, Scotland.

For Zuma, the mission is an opportunity to redeem the African Union as leaders say they are being upstaged on their own turf by other world diplomatic efforts.

"Some international players seem to be denying Africa any significant role in the search for a solution to the Libyan conflict," African Union Commission chief Jean Ping complaint at an extraordinary summit in Ethiopia last week.

"Africa is not going to be reduced to the status of an observer of its own calamities," he warned.

Zuma also has a hurtful bilateral issue to discuss with Gadhafi. South African officials say Gadhafi misled them with assurances that a missing South African photojournalist, Anton Hammerl, was alive and in Libyan custody. Four journalists held in Libya revealed upon their release that Hammerl was shot and killed by government forces on April 5 and left to die in the desert.