South Africa's major port of Durban, where operations were disrupted by severe flooding last week, is now functional and a backlog of thousands of containers will be cleared within five to six days, the public enterprises minister said on Tuesday.

The floods caused extensive damage to roads leading to Durban port, one of the busiest shipping terminals in Africa and a key hub for exports like metals and agricultural commodities and imports like fuel.

Scientists believe the southeastern coast of Africa is becoming more vulnerable to violent storms and floods as human emissions of heat-trapping gases cause the Indian Ocean to warm. They expect the trend to worsen dramatically in coming decades.

Minister Pravin Gordhan told an online briefing on Tuesday that fridges, logs and debris ended up in the harbour during the floods but that after 72 hours of dredging a lot of the debris had been cleared.

He said that trucks could now access the port terminals, which were operating at between 60% and 100% capacity, and that there was no risk of fuel shortages as state logistics company Transnet's pipeline was operational.

Talking about chrome, ferrochrome and iron ore specifically, Gordhan said exports were happening at a "reasonable" level, given the damage that had occurred, and that exports should improve in the coming days.

Trade and industry minister Ebrahim Patel said problems with the movement of goods were shifting from the Durban port, where there had been considerable progress, to the logistics of moving cargo to the Gauteng province, the country's economic hub where Johannesburg is located.

President Cyril Ramaphosa invoked the importance of the Durban port to the country's economy as a whole in an address to the nation on Monday, when he announced that his cabinet had declared a national state of disaster to respond to the crisis.

The floods, among the worst to have affected KwaZulu-Natal province in its recorded history, have killed more than 440, left thousands homeless and damaged more than R10-billion of infrastructure.

Dozens of people are still missing and search and rescue missions continue, although the chances of finding people more than a week after the rains started to lash the east-coast province are shrinking.