Health Minister Zweli Mkhize and his wife, Dr May Mkhize, have tested positive for Covid-19.
The pair tested for the virus on Saturday after they started showing symptoms.
Mkhize said he was showing only mild symptoms, but his wife had a cough and was feeling dizzy and extremely exhausted.
"Given her symptoms, the doctors advised that she must be admitted for observation and rehydration," Mkhize said in a statement on Sunday.
The minister says their contacts, which include a few family members and some members of the health ministry team, have been informed. They have been advised to immediately isolate in their homes, and be tested.
"I am now in quarantine at home, and both my wife and I remain optimistic that we will fully recover from this virus.
"I wish to take this opportunity to urge all South Africans to continue adhering to health protocols. I want to beg that we do not neglect wearing our masks, social distancing, and washing and sanitising our hands," Mkhize said.
The health minister added that the country had made significant strides in its fight against the pandemic.
"Whatever we do and wherever we go, we have to keep in mind that there remains a risk of a second wave. This virus only spreads through movement and contact of people.
"Therefore, we must all play our part. We must protect ourselves and those we love," he said.
Mkhize says that he will use the quarantine period to rest and recharge because the task to improve the health services of the country, and the lives people post Covid-19, remains of paramount importance.