In February he was featured in an article for Public Radio International titled "Twitter and Cocoa Pops: The surprising life of a student in North Korea".
Australia on Thursday said it was "urgently seeking clarification" on the fate of a citizen feared detained in North Korea.
The Department of Foreign affairs said it was in contact with the family of a man named by Korean-language media as Alek Sigley.
Officials said they were in contact with the family of the man "who has been reported as being detained in North Korea".
Australia has no diplomatic mission of its own in Pyongyang and is represented in North Korea by the Swedish Embassy.
Mr Sigley is one of only a handful of Western students at Kim Il Sung University, where he studied Korean literature.
He also runs a company called Tongil Tours which specialising in bringing foreign students to North Korea and has written articles about Pyongyang's dining scene and other issues for NK News.
His last social media posts came three days ago and seemed innocuous enough.
Canberra advises against non-essential travel to North Korea, where several foreigners have been detained.
Consular advice recommends Australians "stay as short a time as possible, eliminate unnecessary activities, and review your security arrangements."
In 2016, Otto Warmbier, a University of Virginia student, was imprisoned during a tour of the authoritarian state after being accused of taking down a propaganda poster.
Doctors said he suffered severe brain damage while in detention, fell into a coma and died days after arriving back in the United States in June 2017. He was 22.
