DURBAN (BLOOMBERG) - Wastewater analysis shows that Covid-19 infections are surging in two major metropolitan areas, said the South African Medical Research Council (SAMRC).

The number of virus fragments found in water samples have jumped this month in Tshwane, the municipal area that includes the capital, Pretoria, and in Nelson Mandela Bay, the municipality that governs the coastal city of Gqeberha, the council said in a statement on Friday (Nov 26).

The finding comes in the same week that South African scientists announced the discovery of a new Covid-19 variant, named Omicron by the World Health Organisation, sparking widespread bans on flights to and from the country and its neighbours.

The National Coronavirus Command Council convenes on Saturday to discuss issues including the new variant, bringing forward a meeting originally planned for Sunday.

"At the beginning of the month, levels of Sars-CoV-2 RNA fragments in wastewater were mostly low or undetectable," Dr Rabia Johnson, deputy director of the SAMRC's Biomedical Research & Innovation Programme, said in the statement.

"Now we're measuring concentrations last seen during the third Covid-19 wave," which peaked in July.

The number of fragments found in wastewater at the Kelvin Jones wastewater treatment plant in Nelson Mandela Bay rose to 20,573 per million litres in the week ended Nov 22, compared with 282 in the week ended Nov 8.

At Tshwane's Refilwe plant, a concentration of 20,989 fragments per million litres was detected in the week to Nov 22.

Tshwane has a population of about 2.9 million, while more than 1.15 million people live in Nelson Mandela Bay.

On Saturday, lobby group Business for South Africa called on the government to restrict workplaces and non-emergency public access areas such as indoor restaurants and taxis to the vaccinated.