Louis Mark Ciavarella, known as Mark Ciavarella, had been living and working in the capital city of Brazzaville as an English teacher.
The 56-year-old did not arrive to a function with colleagues on October 27, and has not been seen since.
His co-workers went to check his apartment, and his laptop and passport were still there.
He last made contact with his family on October 26.
Ciavarella is originally from Leeton in New South Wales.
Australia does not have an embassy in the DRC, with the closest diplomatic representation in Harare, Brazil.
Authorities are working with the Italian embassy in the DRC, as Ciavarella is a dual citizen of both countries.
“The Department of Foreign Affairs and Trade is working with the Italian Embassy in Brazzaville to provide consular assistance to the family of an Australian man reported missing in the Republic of the Congo,” a DFAT spokesperson said.
“Owing to our privacy obligations, we are unable to provide further comment.”
