In a Twitter message on Saturday, Belgian Justice Minister Koen Geens said "multiple searches and arrests" had been made, and that they were related to a vehicle with a Belgian number plate, Reuters reported.
A Belgian car was seen near the Bataclan concert hall in Paris, according to witness accounts.
A Justice Ministry spokeswoman said she could not confirm the precise number of arrests or give any further details.
The website of the public broadcaster RTBF reported that police searches were continuing in the Molenbeek district of Brussels.
It quoted a source close to the operations as saying there had been "between two and three searches, linked to the Paris attacks" and that five people had been arrested.
Late on Friday, a string of coordinated attacks in and around the French capital left at least 129 people dead and some 200 others injured.
A state of emergency has been declared in the European country shaken by the horrific attacks.