The death toll from the ongoing flash floods in Somalia has risen to 29, the national disaster management agency says.

The flooding has left many people injured and affected an estimated 850,000 others, the agency's head, Mahamuud Moallim, said on Tuesday.

Fourteen people had been confirmed killed in the floods on Saturday by the United Nations humanitarian affairs agency (Ocha).

Earlier this week, Somalia declared an emergency in the most affected states - Jubbaland, Hirshabelle South West and Galmudug.

The flooding began last month after heavy rains raised water levels and caused the overflowing of the Juba and Shabelle rivers.

Flash floods have also killed dozens of others in neighbouring Kenya and Ethiopia.

Ocha said in September that East Africa was likely to encounter heavier than normal rains over the October-December period because of the El Niño phenomenon.