Thailand has detected its first case of the Omicron coronavirus variant in a US citizen who had travelled to the country from Spain late last month, a health official said on Monday,

The confirmed case in the man, who had arrived on Nov 29, makes Thailand the 47th country to have found the new variant, Opas Karnkawinpong, director-general of the Department of Disease Control, told a news conference.

Opas said health authorities were conducting further tests of people who had come into contact with the man, but said all contacts so far were low risk.

Thailand banned travellers from eight African countries including Botswana, Eswatini, Lesotho, Malawi, Mozambique, Namibia, South Africa and Zimbabwe at the start of December amid concerns about the Omicron variant.

Opas said authorities had also limited travel from other African countries and were monitoring for more potential cases among international travellers.

Thailand reported 4,000 new coronavirus cases and 22 new deaths on Monday, taking the tally to more than 2.1 million cases and 20,966 deaths since the pandemic started last year.

More than 57% of people in Thailand have received two doses of Covid-19 vaccine, health ministry data showed.