Cyclone Enawo killed at least 50 people and affected 176,000 people after it hit Madagascar earlier this week, the national disaster management agency said Saturday, with thousands forced into emergency shelters.
The toll issued by the head of the BNGRC agency Thierry Venty was significantly higher than the earlier estimate of just four deaths and 10,000 people displaced issued on Thursday.
More than 53,000 people have been displaced and 180 injured by the storm, the agency said in a statement on Friday, while 32,000 have been affected in the capital city Antananarivo alone.
Officials have opened 137 shelters to house those hit by the cyclone.
Enawo hit Madagascar's remote northeast on Tuesday, swelling rivers to bursting point and sparking fears of widespread flooding.
It has weakened since making landfall and has now been reclassified as a tropical depression which is moving southwards, away from the island which lies 250 miles (400 kilometres) off the coast of Africa.
Videos on social media showed flattened trees, flooded roads and corrugated sheeting ripped from roofs after the cyclone struck.
Up to 700,000 people could be affected by the cyclone which was the most powerful to strike the island since 2012, according to the Red Cross.
The group has deployed 500 volunteers to help the 176,000 islanders who are known to have been affected by the storm so far.
In 2012, tropical storm Irina and tropical cyclone Giovanna claimed more than 100 lives.
The Indian Ocean island has suffered severe drought and food shortages since 2015, with the southern region the worst affected.