Chief executive Phakamani Hadebe said a new approach was needed to sustain food security as the world moved towards the 22nd century.

"We really have to review the way we do business. Food security will demand new thinking and a new approach," he said.

Hadebe was briefing reporters in Centurion at the signing of a multi-billion agricultural loan deal between the bank and agricultural services and food group Afgri.

Without sufficient food, Hadebe said human migration across borders was set to swell rapidly.

"The boundaries that we have will diminish over time which means we will see a lot of migration. Countries that appear to be doing better (economically) will attract more people."

Afgri CEO Chris Venter said Africa's thriving population would soon put pressure on the continent's food reserves.

"We want to continue to expand our footprint into Africa. We need this partnership to ensure the sustainability of food security and we can't do that on our own."