The list of 85 individuals included alleged Paris ringleader Abdelhamid Abaaoud, brothers Brahim and Salah Abdeslam and newly named suspect Mohamed Abrini, they said.
The list was sent by the intelligence agencies to the local authorities in Molenbeek, a run-down Brussels district dubbed a haven for extremists, they said.
"I confirm that they featured on a list sent in June 2015 by the Threat Analysis Coordination Agency to the mayor of Molenbeek and the local police chief," a local government source told AFP on condition of anonymity.
Those raids followed the bloody attacks in Paris on the Charlie Hebdo satirical magazine and a Jewish supermarket which left 17 people dead.
The latest revelations will raise fresh concerns about Belgium's handling of a growing Islamic extremist threat, with several major terror plots having roots in the country.
Abaaoud, a Belgian-Moroccan dual national who was killed in a French police raid days after the Paris attacks, is the presumed organiser of the atrocities.
Belgian-Moroccan Abrini is the subject of an international European arrest warrant and was seen driving a car with Salah Abdeslam on the eve of the attacks.
