This was revealed on Friday at a press conference by Construction’s group executive of planning and sustainability.
The proposed port will occupy the site of the former Durban International Airport in Isipingo, about 20km south of the city centre.
Gregg-McDonald said that in 2014 the port handled about 2.7 million containers and this was expected to increase to 7.5 million containers in 2040.
Despite improving efficiency and expanding the current container terminal capacity, by 2025 the port’s facilities would not cope.
Ten other sites had been looked at to expand container facilities, including Richards Bay and Ngqura in the Eastern Cape.
“We are at the point where we are narrowing down the designs,” he said, adding that funding for the project still had to be sourced.