The disease broke out in Mexico; now officials warn of a global pandemic
Two suspected swine flu cases in South Africa have tested negative, say health officials, meaning there are no confirmed cases of the virus in Africa.
Laboratory tests on the women, from Gauteng province and Western Cape, were negative. They had recently visited Mexico, epicentre of the outbreak.
It came as the African Union prepared a continent-wide response for a pandemic.
The World Health Organization has raised the swine flu alert level to warn a global outbreak may be imminent.
Lucille Blumberg, of the National Institute for Communicable Diseases, said the unnamed Gauteng woman had been cleared.
The other woman, Susan Kok, 58, who had just returned from a month-long break in Mexico with her husband, told South Africa's Times newspaper she was "so grateful" after also testing negative.
The African Union has been working on an emergency swine flu response at a conference in Ethiopia.
"We hope to establish a continental plan for prevention, and if necessary a mechanism to fight this outbreak that has not yet affected Africa," AU Peace and Security Commissioner Jean Ping said in Addis Ababa.
Egypt has ordered the nation's quarter of a million pigs to be slaughtered over swine flu fears, in the first such move in the world, even though experts say the virus cannot be transmitted by eating meat.
The authorities in Ghana have banned imports of pork and pork products and the Central African nation Gabon has followed suit.
Health monitoring has been stepped up at ports from Kenya and Ethiopia in East Africa to Senegal and Mauritania in the west.
Heat sensor devices have been introduced at entry ports from South Africa to Morocco in North Africa to detect fever in travellers.
Mozambique has sent medical teams to its main seaports, which are some of the busiest in southern Africa.
And authorities in Nigeria, Africa's most populous country, have said they are ready to cope with any swine flu outbreak.
The WHO raised the alert to the second highest level of five on Wednesday.
Since the virus emerged last week, it has also spread to elsewhere in the US, Canada, Latin America, Europe, Israel, and New Zealand.