Omicron variant found in earlier test samples from November in Netherlands

"In a special PCR test, the samples showed an abnormality in the spike protein," the RIVM said.

"This raised the concern that the Omicron variant of the coronavirus might be involved."

Two samples were confirmed as the Omicron variant. It is not yet clear whether these people had also visited southern Africa.

RIVM has alerted the Municipal Public Health Services (GGDs) in the regions where the samples were taken. The GGD will notify the people involved and start source and contact tracing, Xinhua news agency reported.

The Omicron variant was first reported in South Africa. Last Friday, 624 people arriving from South Africa in the Netherlands were tested for the coronavirus at Schiphol Airport and 61 of them tested positive. In total, the Omicron variant has been found in 14 of those people, according to the latest RIVM data.

"Laboratory tests identified several different strains of the Omicron variant," the RIVM added.

"This means that the people were probably infected independently from each other, from different sources and in different locations."