Gaddafi was elected chairman of the 53-nation AU at its annual summit last year, despite strong opposition from some African leaders, and diplomats say he seeking another term.
The flamboyant Libyan leader, known for his theatrical entrances, wants to stay on despite an agreement among African leaders that the position should be rotated every year.
We know hes coming here to push for another year as chairman and were ready for that, an AU diplomat, who did not want to be named, told Reuters. Countries like South Africa, Ethiopia and Kenya wont stand for it. But hes been sending diplomats to West Africa and offering concessions for support.
Gaddafi showed up for his election as AU chairman last year resplendent in golden robes and a cap, and was hailed as king of kings by traditional African leaders who accompanied him.
AU summits have regularly been dominated by Darfur, Somalia and other conflicts on the worlds poorest continent, although critics say the under-funded organisation is toothless.
Sudans Darfur region and the failed state of Somalia are on the agenda again at the Addis Ababa summit, alongside discussion of Africas four coups last year.
But when leaders arrive on Sunday, diplomats who have spent months preparing for the three-day event fear they will be drawn into marathon arguments with the Libyan leader.
UNITED STATES OF AFRICA
The chairmanship is usually decided on a regional, rotating basis. This year is the turn of southern Africa and they have selected Malawis President Bingu wa Mutharika to succeed Gaddafi.
Delegates to the summit are reluctant to talk about an issue which most regard as delicate for the organisation, especially as Libya is one of most generous donors to its depleted funds.
But Kenyan Foreign Minister Moses Wetangula told Reuters there would have to be serious extenuating circumstances for leaders to agree that one of them could stay on as chairman.
As Kenya, we have not been told or requested to support a continuation, Wetangula said. When we are asked, we will know how to deal with it.
Gaddafi used his new position at last years summit to push leaders into meetings that went on until the early hours of the morning, at which he argued passionately to make his dream of United States of Africa a reality.
Delegates say he wants another year as AU chairman to pressure African leaders to back the idea, which he sees as the only way for Africa to develop without Western interference.
But some countries, usually led by South Africa, argue the plan is impractical and would infringe on the sovereignty of member states even if all agree with the idea in principle.
A member of the Malawian delegation, who did not want to be named, told Reuters they were confident that, after some drawn-out horse trading, their president would take over. We must talk about this possibility, he said. But it will only be talk.