Three of the positive cases were recorded in the Western Cape while one was in Gauteng.
Gauteng remains the epicentre of the outbreak in the country, with the most recorded infections, followed by the Western Cape.
The four patients will be treated in SANDF facilities.
“The SANDF has also identified quarantine and isolation facilities for the military community in preparation for the envisaged overflow in military hospitals and sickbays. These facilities are department of defence establishments with accommodation capacity in all provinces,” it said.
Meanwhile, the defence force stressed that it was doing all it could to ensure the protection of its members as they embarked on their essential-service duties.
“Frontline workers [emergency medical teams, nurses, doctors, porters and soldiers patrolling the townships] have been issued with personal protective equipment.
“Other preventive measures include thermal screening, hand sanitising and wearing of surgical masks,” the SANDF said, adding that it continued to run Covid-19 awareness campaigns for its members.