Cyclone Dineo killed seven people, injured 55 and displaced more than 100,000 as it battered southern Mozambique, natural disasters agencies said Friday.

The National Institute of Disaster Management said that among the 55 people injured, four were in critical condition.

More than 650,000 people in the southeastern African country were also affected since the storm made landfall late Wednesday.

Dineo's impact has been greatest in Inhambane and Vilanculos, two areas popular with tourists on Mozambique's southeast coast, where total rainfall reached 100 to 200 millimetres.

Inhambane was struck by winds of more than 100 kilometres (62 miles) per hour and battered by torrential rain and rough seas.

Many of the city's roads were blocked by fallen trees or crippled by severe flooding. Several neighbourhoods were left without electricity.

According to data given to the International Red Cross by Mozambican authorities Friday, 130,000 people were displaced by the storm, while 22,000 homes were partially or completely destroyed.

The storm also damaged 49 hospitals and health centres and 105 schools and public buildings.

The Red Cross and the Red Crescent sent emergency teams and materials to the affected areas, in particular to ward off serious health risks.

"The displacement of families, the interruption of health services related to severe flooding and water contamination present serious public health risks that need to be treated quickly," said Jamie LeSueur, the Red Cross coordinator for southern Africa.

Mozambique, one of the world's poorest countries, is often battered by deadly flooding and storms.

In 2000, floods claimed at least 800 lives, and more than 100 were killed in 2015.

Scores have already died in the current rainy season, which began in October.

Dineo was downgraded to a tropical depression on Thursday and renamed "ex-Dineo".

The South Africa Weather Service warned that the storm still posed a threat of heavy rainfall and flooding as it headed inland into South Africa, Zimbabwe and Botswana on Friday.

The service put out a red alert for the provinces of Mpumalanga and Limpopo, in north and northeast South Africa, which are at risk of heavy rains and severe flooding.

Kruger National Park, the country's premier safari destination, closed its gravel roads and several camps because of the storm. No major damage was reported as of Friday evening.

"In all of these countries, people are especially vulnerable due to the two years of drought, food shortages and loss of their livelihoods," LeSueur said.

"It's a source of great concern."