Zimbabwe's state power utility, ZESA, said on Tuesday it had restored power to most of the country after a fault on a key transmission line caused a nationwide blackout on Monday evening, while work continued to bring remaining generation units back online.

The outage began at 1824 local time (1624 GMT) after a major fault on the Warren-Alaska 330-kV line disrupted interconnections with neighbouring power utilities and subsequently caused local generation to trip due to voltage instability and under frequency.

Power was restored with supplies from South Africa's Eskom, Kariba Power Station, Hydro Cahora Bassa and three units at Hwange Power Station, with electricity returning to most of the country by 2200 local time, ZESA said.

The utility said its technical teams were continuing work to restore and synchronize the remaining units at Hwange Power Station and to carry out repairs at the Warren substation, which supplies parts of the capital, Harare.

Zimbabwe has long grappled with power outages, worsened by ageing infrastructure and foreign currency shortages that have limited the country's ability to pay for electricity imports.