Floods in the southern African country have already cost at least 18 lives and destroyed homes, livestock and crops. The government says 92,000 people have been rescued. Mozambique said early this month that 200,000 were at risk.

Authorities said on Sunday that the "Fame" storm system had intensified into a full-scale cyclone. Its centre was just off the coast and it was expected to hit flooded river valleys and bring heavy rains to the north and centre.

The flooding has put pressure on aid agencies to provide shelter, sanitation and water. It has also heightened fears of cholera and malaria in the country of over 20 million where the average life expectancy at birth is little more than 40 years.

Ribeiro told Reuters some families in the central Zambezia and Sofala provinces and in the northern Tete province had refused to abandon flooded homes.

"The peak of the rainy season is just two weeks ahead and this is not the time to raise awareness. We will forcibly remove anyone in those areas we declared risky," Ribeiro told Reuters.

"Men risk their lives in order to save goats and chickens along the Zambezi valley which they treasure as their wealth, but our mission is to save their lives," he said.

The United Nations has said the current floods in Mozambique could be worse than those of 2000-2001, which caused the deaths of 700 people.

Mozambique's National Emergency Operational Centre warned provincial authorities about the cyclone and advised them to stockpile food and clean water.