The operating licences of radio stations FIM FM, Radio Espace FM, Sweet FM and Djoma FM, as well as Djoma TV, were withdrawn over a "failure to comply with the content of the specifications," it said, without further detail.
The ban follows a string of restrictions imposed on the media by the junta, which seized power in the West African nation in 2021.
"The repression of the media must stop," wrote media watchdog Reporters Without Borders (RSF) on X, formerly Twitter, adding that the authorities had committed to "unblocking an already dramatic situation" for media outlets.
Four private radio stations have been constantly jammed since November, three private television channels are virtually inaccessible, and at least three news sites were blocked for several weeks in 2023, according to RSF's website.
At the end of 2023 and beginning of 2024, the authorities also restricted internet access for several weeks and detained a press union leader for more than a month, prompting a general strike.
Guinea is ranked 78th out of 180 countries in the watchdog's 2024 press freedom ranking.
The junta banned all demonstrations in 2022 and has arrested a number of opposition leaders, civil society members and the press.
The crackdown on protests in Guinea has left at least 47 people dead, mostly young people, since 2021, Amnesty International said in a report this month.
The military agreed under pressure from regional bloc ECOWAS to organize elections by the end of 2024, after a so-called transition period which it said would allow for reforms.
But junta-appointed Prime Minister Amadou Oury Bah has said in recent weeks that the military will not be able to honor the commitment and should remain in power until at least 2025.
Junta chief General Mamady Doumbouya has remained silent on the issue.
The FNDC, a civil society collective which has spearheaded protests in recent years, on Tuesday threatened to resume demonstrations if the junta did not commit to handing back power by the end of the year.
An opposition coalition, the National Alliance for Alternation and Democracy (ANAD), made the same demand on Saturday.