Concrete walls and floors caved in on hundreds of mostly teenage boys at the Al Khoziny Islamic boarding school in East Java province on September 30.
Most managed to escape.
Mohammad Syafii, head of Indonesia's search and rescue agency, said more bodies and body parts had been found, raising the confirmed death toll to 65.
It remained unclear how many people were still missing.
Syafii told reporters the search operation would continue until rescuers were "sure that no victims are left".
Authorities have said the cause of the collapse was construction work on the upper floors that the school's foundations could not support.
Footage shared by the search and rescue agency showed recovery workers carrying orange body bags out of the ruins.
Across Indonesia, there are about 42,000 Islamic school buildings, known locally as pesantren, according to data from the religious affairs ministry.
Only 50 have building permits, however, public works minister Dody Hanggodo was quoted as saying by local media on Sunday.
It is not clear if Al Khoziny had a building permit.
Reuters could not immediately contact school authorities for comment.
