South Africa has signed a nuclear energy cooperation agreement with China as the government looks to expand the critical power supply system, officials said Friday.

Pretoria said the agreement was a "preparatory phase for a possible utilisation of Chinese nuclear technology in South Africa".

The energy ministry said in a statement that the government had committed to expanding nuclear power generation by an additional 9.6 gigawatts by 2030.

The country has already signed similar agreements with Russia and France, potentially putting firms Rosatom and Areva in line for the development of nuclear reactors worth billions of dollars.

South Africa currently has only one nuclear plant, located outside Cape Town, and the country relies heavily on coal-fired power stations for electricity generation.

Power supply has come under severe strain in Africa's second biggest economy as the state-owned electricity producer Eskom battles to meet rising demand, often resulting in blackouts.

Electricity constraints have been blamed for limiting economic growth and productivity.