South Africa on Sunday declared a national disaster after widespread flooding that destroyed homes and killed dozens, while thousands sought shelter in neighbouring Mozambique.

Heavy rains and storms have hit the two southern African countries for weeks, claiming more than 30 lives in South Africa's northeastern Limpopo and Mpumalanga provinces.

Rivers burst their banks and flooded entire neighbourhoods in several regions of Mozambique, displacing thousands of people.

"I classify the disaster as a national disaster," the head of South Africa's National Disaster Management Centre Elias Sithole said in a statement Sunday.

Search and rescue continues

Authorities continued to search for survivors and recover bodies at the weekend, but flooding had started receding in some areas, including the famed Kruger National Park, which had been forced to close and evacuate guests on Thursday.

"Day visitation to the park will resume as of tomorrow," South African National Parks announced on social media, still urging visitors to "exercise caution."

In Mozambique, at least eight people have died since December 21, according to official data.

South Africa also dispatched rescue teams to southern Mozambique on Sunday after a car carrying five members of a South African mayoral delegation was swept away by floodwaters in Chokwe, 200 kilometres north of Maputo.

According to the latest figures released by the Mozambican government on Friday, more than 173,000 people had been affected by the floods across the country.