Fifty-five people drowned, or are presumed dead, after an overcrowded boat capsized off the Somali coast, the UN refugee agency has said.

The UNHCR said it is the worst such incident since February 2011, when 57 Somali migrants perished attempting to reach Yemen.

The agency quoted five of the survivors as saying the boat was overcrowded and ran into trouble almost immediately after leaving the port of Bosaso, in the northern Somali region of Puntland.

It capsized just 15 minutes into its journey on Tuesday, spilling all 60 passengers into the sea.

Those on board were Ethiopians and Somalis, the UNHCR said.

So far, 23 bodies have been recovered, including those of 14 women, eight men, and a boy said to be less than four years of age.

Five of the dead are confirmed to have been Ethiopians. The 32 remaining passengers are presumed to have drowned.

"Without doubt, the Gulf of Aden is now the deadliest route for people fleeing conflict, violence and human rights abuses in the Horn of Africa," said UNHCR Representative for Somalia Bruno Geddo.

African migrants often use unseaworthy boats to try to reach Yemen, seen as a gateway to wealthier parts of the Middle East and the West.

Hundreds of migrants have perished at sea.

The UNHCR estimates that 100,000 people have crossed the Red Sea and the Gulf of Aden this year, despite warnings about the risks.

The latest deaths bring the number of those drowned or missing in the waters between Somalia and Yemen this year to 95.