Sky Plaza, in Leeds city centre, closed last year as a precaution in the Grenfell Tower disaster over concerns about its external cladding and safety procedures.
The building, run by Unite Students, will have its exterior cladding removed, and replaced with cladding that has passed UK building control tests.
Bosses at the company say the work is expected to be completed by the summer, and the site will be ready for students in September.
It comes after West Yorkshire Fire and Rescue Service (WYFRS) said in July that Sky Plaza was among five buildings in the middle of Leeds that had failed what it described as “cladding combustibility” tests.
A spokesperson for Unite Students said: “Today we start work to upgrade the building and facilities at our Sky Plaza property in Leeds.
“Our highest priority is always the safety of our students, and this refurbishment continues to ensure Sky Plaza meets the most stringent health and safety measures whilst providing a comfortable and safe home for our students. The works are expected to be completed by the summer and will include the installation of a brand new sprinkler system amongst other health and safety features.”
Other sites that failed WYFRS’ tests in July included the Park Plaza Hotel, in Boar Lane, and Concept Place, run by United Students, off Park Lane.
Waterside Apartments, in Gotts Road, and Waterloo Court Apartments, near Hunslet Road, also failed the tests.