Somalia is to hold its presidential election on Wednesday after numerous delays, with ongoing security concerns and warnings of famine topping the agenda for the new administration.

President Hassan Sheikh Mohamud is seeking re-election against 22 other candidates.

The troubled Horn of Africa nation, which has not had an effective central government in three decades, had been promised a one-person, one-vote election in 2016.

However political infighting and insecurity, mainly due to Al-Qaeda linked Shabaab militants who control swathes of countryside and strike at will in Mogadishu, saw the plan ditched for a limited vote running months behind schedule.

The presidential election had been due to take place in August, four years after the previous vote in which just 135 clan elders chose MPs who then voted for the country's leader.

Elections instead began in October with an electoral college system that excluded ordinary citizens and instead involved 14,025 delegates voting for candidates for both parliament and a new upper house.

The elections were marred by widespread allegations of vote-buying and intimidation.

In a report on Tuesday, Somalia-based anti-corruption watchdog Marqaati said the elections "were rife with corruption". Repeated delays meant the new lawmakers were only sworn in in December.

- Delays and disillusion -

The tortuous process has left some disillusioned. "I really don't care who becomes president. We just need to be free to attend to our business," said Qoje Siyad, a Mogadishu day labourer.

"This thing is taking too long," said housewife Samiya Abdulkadir. "People will be relieved to see an end to this drama."

While falling well short of the election that was promised, the process is more democratic than in the past and is seen as a step towards universal suffrage, now hoped for in 2020.

Wednesday's voting will see members of the 275-seat parliament and 54 senators cast ballots inside a hangar within the heavily-guarded airport.

No candidate is expected to get the two-thirds majority needed for a first-round win, with two further rounds permitted before a winner is declared.

In the absence of political parties, clan remains the organising principle of Somali politics.

All 23 candidates are men after the only declared female candidates dropped out.

And each one has paid the $30,000 (28,000-euro) registration fee although few have any serious chance of winning.

One of them is the current president, a 61-year-old former academic and civil society activist from the Hawiye clan.

Also in the running is ex-president Sharif Sheikh Ahmed, a fellow Hawiye and 52-year-old former leader of the Islamic Courts Union which pacified Somalia before being driven out by US-backed Ethiopian troops.

The leading Darod candidates are Prime Minister Omar Abdirashid Ali Shamarke, 56, and a former premier Mohamed Abdullahi Mohamed 'Farmajo', 55.

Both hold dual nationalities having lived for years in Canada and the US respectively.

- Famine looms again -

The overthrow of president Siad Barre's military regime in 1991 ushered in decades of anarchy and conflict in a country deeply divided along clan lines.

The clan rivalries and lawlessness provided fertile ground for the Al-Qaeda linked Shabaab to take hold and seize territory, frustrating efforts to set up a central administration.

Shabaab has been in decline since 2011 but still launches regular, deadly attacks against government, military and civilian targets in the capital Mogadishu and elsewhere.

Security and overcoming Somalia's adversarial and divisive politics will top the agenda for whoever wins the vote as will dealing with a growing humanitarian crisis.

The UN warned last week of "possible famine" in Somalia as a severe drought has pushed nearly 3 million people to the edge of starvation.

After two failed rain seasons, aid workers fear a repeat of a 2010-11 drought which left more than 250,000 dead.

"The levels of suffering in the country, triggered by protracted conflict, seasonal shocks and disease outbreaks, are typically hard to bear, but the impact of this drought represents a threat of a different scale and magnitude," the UN's office for humanitarian affairs said in a statement last week.