Police in South Africa are investigating the hijacking of a lorry that was carrying Covid-19 samples in the city of Port Elizabeth.

The lorry was hijacked while parked outside a clinic on Monday and abandoned shortly after, public broadcaster SABC reports.

The samples are reported to be missing. They were contained in cooler boxes filled with ice.

Health authorities have warned the hijackers and the public not to touch the samples because they are potentially highly infectious, the News24 website reports quoting an official from the National Health Laboratory Services in Eastern Cape province.

Health officials are investigating the number of samples stolen before determining how many people to retest, the website adds.

Some 2.5 million coronavirus tests have been conducted in South Africa.

The country has the nighest number of confirmed cases on the continent.