At least 66 people have been killed and 141,000 affected after heavy rains deluged central and northern Mozambique, the government has said.
The government has also appealed for funds to manage the disaster.
“The government has decreed a red alert due to the continuing rains and the approach of the tropical cyclone Idai, expected to reach the country between Thursday to Friday,” said cabinet spokeswoman Ana Comoana.
She spoke to reporters late Tuesday after a cabinet meeting in Maputo to discuss the emergency.
The floods in one of Africa’s poorest countries have already destroyed 5,756 homes, affecting 15,467 households and 141,325 people.
In neighbouring Malawi, floods have already claimed 45 lives and left over 230,000 people without shelter.
Malawi’s Meteorological Department has warned of more rains and flooding in the country’s south between Thursday and Sunday.
In Mozambique, 111 people have been injured, 18 hospitals destroyed, 938 classrooms destroyed and 9,763 students affected.
More than 168,000 hectares (415,000 acres) of crops were destroyed, the government spokeswoman added.
Authorities have ordered the compulsory evacuation of people living in flood-prone areas.
“Sixteen accommodation centres have been opened in the provinces of Zambezia and Tete to accommodate the displaced,” Comoana said.
“The government needs 1.1 billion meticais ($16 million) to assist 80,000 families affected by the rains”.
Mozambique is prone to extreme weather events. Floods in 2000 claimed at least 800 lives while more than 100 were killed in 2015.