South African President Cyril Ramaphosa on Thursday defended his decision to appoint a minister to try to end crippling power cuts, rejecting criticism the role would cause confusion in government.

State utility Eskom is implementing the worst power outages on record, constraining the country's economic growth prospects. That prompted Ramaphosa to declare a "state of disaster" and say he would appoint a new Minister of Electricity last week.

Some lawmakers said the appointment would add a layer of bureaucracy as Eskom is overseen by the public enterprises minister while the energy minister is responsible for procuring additional power generation capacity.

Ramaphosa told parliament some people had suggested the appointment will "result in turf wars amongst the ministers who deal with energy and Eskom".

"This is not the case," he said, responding to a debate by lawmakers on his State of the Nation Address.

"(The power crisis) requires the undivided attention of a political principal who does not need to split their time and energies among different important responsibilities," he added.

South Africa has previously invoked disaster management law to address the Covid-19 pandemic and flooding in its KwaZulu-Natal province.

Ramaphosa said declaring a "state of disaster" would remove unnecessary bureaucratic obstacles to urgently adding power capacity to the grid.

Creaking coal-fired power stations, corruption in coal supply contracts, criminal sabotage and failure to relax regulation to enable private providers to swiftly bring renewable energy online have left South Africa with a deep power deficit.