Somali lawmakers are expected to pick the country's new president on May 15, a parliamentary committee said on Thursday, the final step in a tortuous election process that has suffered delays due to a rift within the outgoing administration.

The selection of a president is a key step in establishing a new government, which must be in place by May 17 if Somalia is to continue receiving budget support from the International Monetary Fund on which it relies to pay essential bills.

Riven by civil war since 1991, the Horn of Africa country has been struggling to rebuild its institutions in the face of a brutal insurgency by the Islamist group al Shabaab, which is linked to al Qaeda.

The central government or allied forces control the capital Mogadishu and most of the main cities, but swathes of the countryside, especially in central Somalia, are under al Shabaab control.

The election process was destabilised by al Shabaab attacks as well as feuding between President Mohamed Abdullahi Mohamed and Prime Minister Mohamed Hussein Roble.

Last year, the president tried to extend his four-year term by two years but was thwarted by parliament.

Under Somalia's indirect electoral process, clan elders select the 275 members of the lower house, who in turn choose the president. More than a dozen candidates are expected to compete.

Somalia's information ministry on Thursday told police to stop a group who were trying to organise pre-election presidential debates, saying they had not been issued a broadcast license.