Thousands stranded in Malawi as floods trigger 'slow tsunami'

Thousands of people in flood-hit southern Malawi are still stranded without aid as a "slow tsunami" continues to hamper rescue efforts, led by the country's army.

Heavy rains and floods have killed 176 people and displaced 110,000, Vice President Saulos Chilima said after touring the worst-hit parts of the southern African country.

"Efforts to rescue thousands of people are becoming difficult because of bad weather and many roads are inaccessible either because bridges have been washed away or simply because there is too much rain," Chilima told reporters on Friday.

The landlocked nation is one of the world's poorest states, with a population of 16 million. Half of the country has been declared a disaster zone after torrential rains swept away crops, bridges and roads.

Up to 20,000 people around Malawi's southern tip are without food, healthcare or clean water, the medical charity Medecins Sans Frontieres (MSF) said in a statement on Friday, with helicopters offering the only chance of assistance.

"The floods are behaving like a slow tsunami with the river swelling progressively downstream towards the south and Mozambique," said Amaury Grégoire, MSF's head of mission in Malawi, referring to the River Shire, the country's largest.

"Most of Nsanje and East Bank are submerged under two to three meters of water, which has transformed these vast plains into a giant lake engulfing houses and bridges."

The United Nations' World Food Programme (WFP), one of several relief agencies rolling out assistance, said 110,000 people had been displaced, an increase from a government estimate of 70,000 earlier this week.

The agency is airlifting more than 100 tons of high-energy biscuits to meet the immediate needs of those affected.

Malawi's weather service has warned of further rainfall and flash floods in the country for the next two to three weeks.

Neighbouring Mozambique has also been badly hit, with a major road destroyed and the South African military helping to search for missing people.