The two professors at the American University of Afghanistan were seized Sunday evening and no group has so far claimed responsibility for their abduction.
"Two foreign professors, one American and the other Australian, were abducted at gunpoint by a kidnapping gang from Dar-ul-Aman road in the center of Kabul city," a security official told AFP.
"We refrain from further comment in order to not damage police rescue efforts."
The kidnapping comes just two weeks after the rescue of an Indian charity worker, who was also taken at gunpoint near her residence in the heart of the city.
The US State Department said it was aware of reports of the kidnapping of an American citizen, but declined to comment further.
The Australian government confirmed the "apparent kidnapping" of one its citizens, citing its embassy in Kabul, but also refused to elaborate due to security considerations.
"We continue to advise Australians not to travel to Afghanistan because of the extremely dangerous security situation, including the serious threat of kidnapping," the government said in a statement.
The abductions underscore the growing dangers faced by foreigners in Afghanistan.
A group of tourists, including British, American and German nationals, came under Taliban fire Thursday in the western province of Herat, leaving some of them wounded.
Aid workers in particular have increasingly been casualties of a surge in militant violence in recent years.
The Indian charity worker, 40-year-old Judith D'Souza who was a staff member of prominent NGO Aga Khan Foundation, had been abducted on the night of June 9.
D'Souza's abduction came after Katherine Jane Wilson, a well-known Australian NGO worker, was kidnapped on April 28 in the city of Jalalabad, close to the border with Pakistan.
Wilson, said to be aged 60, ran an organization known as Zardozi, which promotes the work of Afghan artisans, particularly women.
The United States in May warned its citizens in Afghanistan of a "very high" kidnapping risk after an American narrowly escaped abduction in the heart of Kabul.
In April last year the bullet-riddled bodies of five Afghan workers for Save the Children were found after they were abducted by gunmen in the strife-torn southern province of Uruzgan.