In its bulletin tracking the progression of the H1N1 virus in Africa, WHO said it was putting in place a sub-regional crisis management team in Zimbabwe and two other countries to increase surveillance.
The team will work closely with other teams on the continent to ensure swine flu is detected and control measures are taken early on.
Unconfirmed reports indicate more than 300 schoolchildren in Manicaland Province and an undisclosed number at St Francis of Assisi High School in Chivhu, Mashonaland East, might have contracted the virus.
Ministry of Health and Child Welfare officials yesterday said they were still investigating the reports.
The WHO bulletin said all countries in Southern Africa had activated their national emergency preparedness and contingency response plans.
"A crisis management team has been put in place by the regional director at the regional office (Congo-Brazzaville) and the sub-regional levels (inter-country support teams in Harare, Gabon and Burkina Faso).
"The teams will work closely with countries to boost their disease surveillance to ensure that any suspected case of Pandemic H1N1 2009 is detected early," the global health body said.
The UN body said stockpiles of relevant medicines had been dispatched to all countries in the region.
"Our advice to the public is not to panic but to take necessary preventive measures such as hand hygiene and respiratory etiquette in households, the community, health care facilities as well as in other settings where people gather."
As of Wednesday, WHO said the region had recorded 8 187 confirmed cases of swine flu and 41 deaths in Africa with South Africa topping the list with 7 606 confirmed cases and 31 deaths. Kenya is second with 85 cases and Mauritius next with 69 cases each but neither country has recorded deaths.
Other H1N1 virus deaths in the sub-region were recorded in Lesotho with 12 and Namibia with one.