PORT LOUIS/ANTANANARIVO: Mauritius grounded flights and shut its stock exchange as tropical cyclone Freddy approached the island in the Indian Ocean on Monday, while emergency teams braced for heavy rains, floods and landslides in four regions on Madagascar.

The cyclone, packing wind gusts of up to 120 km per hour (75 miles per hour), posed a direct threat to Mauritius, its weather service said.

"As Freddy approaches ... (a) storm surge is likely to cause coastal inundation in risk areas. It is, therefore, strictly advised" not to go to sea, the service's bulletin said.

The cyclone could pass as close as 120 km (75 miles) to the north-northwest of the island late in the afternoon, the service said.

A video verified by Reuters showed strong winds and waves hitting an oceanfront hotel in Mauritius as water entered the lobby of the hotel as guests and staff looked on.

Authorities on the island of Madagascar - about 1,130 km west of Mauritius towards the coast of Africa - said they were expecting a direct hit by late Tuesday, between Mahanoro in the east and Manakara in the south east.

"Torrential rains... very high to enormous seas... and a significant risk of coastal flooding are particularly to be feared in the localities around the point of impact," Madagascar's weather service said.

The government's disaster management office was sending tents, ropes, chainsaws and other supplies to four districts most likely to be affected by the storm, officials added.

The Indian Ocean islands and Mozambique on Africa's coast have been hit by a string of deadly storms and cyclones that have forced thousands to flee, destroyed buildings and ruined crops.

In January, tropical storm Cheneso killed 33 people in Madagascar.