Hailemariam Desalegn, who was appointed Ethiopia's acting prime minister on the death of long-time ruler Meles Zenawi last month, will be formally sworn into office on Friday, officials said Wednesday.

"The party council felt that an extraordinary session should be held on Friday... the two officials, the two chairs who have been appointed, will be sworn in," said government spokesman Shimeles Kemal, referring to Hailemariam and his deputy.

On Saturday, Hailemariam, 47 and a water engineer by training, was elected to the head of the ruling coalition, the Ethiopian Peoples' Revolutionary Democratic Front (EPRDF).

Education minister Demeke Mekonnen, who was elected deputy chair of the EPRDF, will take over the post of deputy prime minister from Hailemariam.

The EPRDF is made up of four parties, each representing a specific region: Meles's party the Tigrayan People's Liberation Front, the Oromo Peoples' Democratic Organisation, the Amhara National Democratic Movement and the South Ethiopian Peoples' Democratic Movement, the party of Hailemariam.

It holds an overwhelming parliamentary majority.