Dr Narong said he signed four documents declaring EVD a dangerous infectious disease that must be reported when found and to warn people of the outbreak in the west African countries of Guinea, Liberia, Sierra Leone and Lagos in Nigeria.
Dr Opas Kankavinpong, deputy director-general of the Department of Disease Control, said Thailand faced a low risk from EVD.
Since June 8, 483 people had arrived in Thailand from Guinea, Sierra Leone and Liberia. None had shown any symptoms of EVD.
Seventy-nine people remained under close watch as they were still in the 21-day incubation period. They include one Thai.
Dr Opas said Thailand could import and use an experimental Ebola vaccine, ZMapp, if it was deemed necessary, even though the World Health Organisation (WHO) had not approved its use on humans due to lack of testing.
The WHO has reported 1,848 cases of EVD of which 1,013 were fatal. The fatality rate has fallen from 90% to 50-60% thanks to growing experience in handling the disease, WHO said.