Heavy rains and gale force winds pelted northeastern Madagascar Wednesday as strengthening tropical cyclone Felleng barrelled toward the island's east coast.

Winds of around 175 kilometres an hour (109 miles an hour) churned the Indian Ocean, giving residents in Africa's largest island just hours to prepare.

Wind speeds are expected to almost double as the vast storm nears land, according to Raymond Randriatahina, head of the national disaster management agency.

NASA has forecast that Felleng will increase intensity and move southwards, tracking down the eastern coast of the country.

With the eye of the cyclone expected to come within 200 kilometres of Madagascar's eastern coast on Thursday, the authorities have announced coastal schools and those in the capital Antananarivo will be closed.

Rising waters have already hit the capital, where the Mamba river flooded 200 hectares of paddy fields.

Authorities were preparing to evacuate people living in the city's low-lying areas with waters predicted to reach alert levels by Friday.

Rescue teams travelled to the north east Wednesday to help local residents.

Madagascar is one the world's islands most vulnerable to cyclones. In the past decade 45 tropical storms have hit.

Cyclone Giovanna and tropical storm Irina last year killed 112 people and affected 90,000.