JOHANNESBURG - A mine dam wall collapse in South Africa's Free State province swept away houses and cars on Sunday, the provincial government said, killing three people and injuring another 40.

The disaster occurred in the mining town of Jagersfontein at around 6am local time (12pm Singapore time), the government said, forcing officials to evacuate scores of residents to nearby farms.

Three bodies have been recovered, while 40 people, including one pregnant woman and four individuals with fractured limbs, have been taken to hospital for treatment.

The government said in a statement that search-and-rescue efforts are continuing at the dormant diamond mine, which was once owned by De Beers, a unit of mining company Anglo American.

"A detailed report on the circumstances surrounding the incident will be released upon compilation," the office of the Free State Premier said.

State-owned power utility Eskom said in a separate statement that it lost bulk electricity supply in the area when its Rietkuil substation was engulfed by mud and aims to restore supply to the Jagersfontein mine before the end of the day.

"It is impossible to estimate when supply will be restored or to determine the extent of the damage," Eskom said.

The flooding damaged cellphone towers, hitting communications and affected drinking water, while some roads were cut off.

Many sheep have also been washed away, said non-governmental organisation Gift of the Givers.

At the time of the sale of the Jagersfontein mine and tailings in 2010 to Superkolong Consortium, which comprised black investors, De Beers said it had produced some of the world's largest gems when operating between 1870 and 1971. REUTERS