Spain said Monday it had detected its first case of the new Omicron strain of Covid in a man who had recently arrived from South Africa.

The 51-year-old was tested when he arrived at Madrid airport on Sunday via Amsterdam and was found to be positive, the regional government of Madrid said in a statement.

"The patient has light symptoms and is undergoing quarantine," the statement added.

Earlier on Monday, Madrid's Gregorio Maranon Hospital tweeted that its microbiology service had detected the first case of the Omicron variant in Spain, without giving further details.

The World Health Organization has listed Omicron as a "variant of concern" and countries around the world are now restricting travel from southern Africa, where the new strain was first detected, and taking other new precautions.

The WHO says it could take several weeks to know if there are significant changes in transmissibility, severity or implications for Covid vaccines, tests and treatments.

Several other European nations, including Belgium, Britain and Germany have detected cases of the variant, which was first detected in South Africa.

Spain has been hard hit by the pandemic, recording nearly 88,000 deaths and 5.1 million infections since it started.