Deputy bureau chief Pol Maj-General Archayon Kraithong said the agency and public health officers are tracking down the rest of the travellers.
He added that some 500 tourists from the other 46 countries have tested negative to Covid-19.
He also confirmed that the Immigration Bureau has tightened checks on foreign arrivals after the discovery of the Omicron Covid-19 variant.
As of December 1, Thailand banned flights from eight counties in the south of Africa, namely Botswana, Eswatini, Lesotho, Malawi, Mozambique, Namibia, South Africa and Zimbabwe.
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