Heavy rains and flooding in southern Malawi have killed at least 23 people, and a further 11 are missing, the ministry of homeland security said on Friday.

Search and rescue teams have been deployed, and more than 22,000 households, or 110,000 people, were affected by the floods, Homeland Security Minister Nicholas Dausi said in a statement.

Power-generating capacity and water supplies have been knocked out in some areas.

Around 270 megawatts of Malawi's 320 megawatts of available hydropower capacity was offline, electricity company EGENCO said in a statement, adding that teams were working to restore power supplies and clear debris at power stations.

Malawi generates hydropower along the Shire River which flows out of Lake Malawi.

Malawi relies heavily on financing from foreign donors and is an importer of fuel and other essential commodities.