Tertiary Education Minister Steven Joyce says it is now unlikely any survivors will be pulled from the collapsed Canterbury Televsion (CTV) building in central Christchurch.
Mr Joyce says it will be some time before it is known how many language school students were inside the building, which is in ruins following the 6.3-magnitude earthquake on Tuesday.
The minister on Sunday met directors of King's Education language school, along with the Chinese and Japanese ambassadors.
The directors said a day earlier that they believed nine staff and 52 students were presumed to have been in the building.
Twenty-six students from Japan, 14 from China, seven from the Philippines, three from Thailand, one from Korea and one from the Czech Republic were among the group.
Mr Joyce says the school now has access to student details on a backup computer server and more information is coming in every day and it is a "very fluid situation."
He says a student contacted the school on Sunday morning to say he was safe.
The building also housed Canterbury's regional television station and a nursing school.