JOHANNESBURG (AFP) - The highly-contagious Delta variant is driving the surge in new Covid-19 infections in South Africa, the government and scientists said on Saturday (June 26) as the country mulled tighter restrictions.

The hardest-hit country in Africa recorded 18,762 new infections on Saturday - its highest daily figure since January - taking the total number of laboratory-confirmed cases to 1,895,905, of which 59,621 have been fatal.

"We are in the exponential phase of the pandemic with the numbers just growing very, very, extremely fast and will keep growing in the next weeks," Prof Tulio de Oliveira of the Network for Genomic Surveillance in South Africa told a virtual briefing.

To curb the spread, "we are going to need that we go to hard, tighter restrictions... and that needs to be done urgently," Prof Koleka Mlisana, the head of a government ministerial advisory committee on Covid-19 said during the briefing.

Health officials across the world have been alarmed by the rapid spread of the Delta variant first seen in India.

World Health Organisation chief Tedros Adhanom Ghebreyesus said on Friday that Delta is the most contagious Covid-19 variant and it has now reached at least 85 countries.