Heavy rains and storms have battered the two southern African countries for weeks, claiming at least 150 lives, according to authorities.

Thirteen people had died in Mozambique since January 12, according to the National Disasters Management Institute (INGD) database which showed that 111 had been killed since October.

Large parts of the country were still underwater, prompting President Daniel Chapo to cancel his trip to the World Economic Forum in Davos.

Rivers burst their banks and swallowed entire neighbourhoods in several regions of Mozambique, displacing thousands including a woman who was forced to give birth on a roof as she sheltered from flood waters.

Images on social media showed parts of the city of Xai Xai, around 200 kilometres (125 miles) northeast of the capital Maputo, were underwater on Monday.

South Africa's defence force said it had sent a search and rescue team, including a helicopter, to assist Mozambique's emergency operations.

South Africa declared a national disaster on Sunday after flooding destroyed homes and killed dozens in the northeastern Limpopo and Mpumalanga provinces.

The death toll had risen to 38 for both provinces since mid-December, the government confirmed Monday after more bodies were recovered overnight.