Mr Hailemariam’s appointment coincides with the celebrations of the 50th anniversary of the founding of the Organisation of African Unity (OAU), the predecessor of the AU, which took place in Addis Ababa, on May 23 1963.
Ambassador Dina Mufti, spokesman for the foreign affairs ministry, insisted that the election of Mr Hailemariam in the golden jubilee year — the focal point for the commemoration will be the Ethiopian capital — was not deliberate.
"It’s not to coincide with the celebrations," he said. "But whether it is coincidental or not, it has outstanding significance for us, in the sense that Ethiopia was the birthplace of the AU."
The announcement of Mr Hailemariam’s chairmanship also breaks AU protocol. The election of the chairman, who strictly rotates between the continent’s five regions, usually takes place on the first morning of the January meeting of the AU Assembly of Heads of State of Government, due this year on January 27.
According to Mr Dina, the decision that Ethiopia would hold the organisation’s top job this year was taken two years ago, when it would have been expected that the late prime minister Meles Zenawi would have assumed the role.
Solomon Dersso, senior researcher at the Institute for Security Studies in Addis Ababa said the decision that Ethiopia would take over from Benin emerged during the AU’s July summit.
"This gives Hailemariam a chance to pursue the agenda that Meles was passionate about," said Mr Dersso. "This includes issues relating to the strengthening and enhancement of the Nepad (New Partnership for Africa’s Development) process, providing leadership and drawing attention to the negotiations on climate change and most important, at a regional level, for addressing peace and security issues."
He believes Mr Hailemariam, who replaced Meles after his death in August last year, will use his position as AU chairman to highlight negotiations between Sudan and South Sudan. Ethiopia has been playing a pivotal role in facilitating the talks.
Mr Dersso said the prime minister would also be a strong advocate for Somalia’s new government.
The celebrations of the 50th birthday of the OAU will begin on January 27 and continue until May 25. "This is an African joyous moment. We are celebrating our achievements in liberation, our achievements in economic progress, our achievements in peace and security," Mr Dina said.