The group was charging between €250 and €300 ($270-320) per person to bring them from Serbia and Hungary, raking in more than €500,000, Interior Minister Johanna Mikl-Leitner said.
A total of 17 people are under investigation, 11 of whom have been arrested.
Police have so far seized around €50,000 and have also impounded six vans used for transporting the migrants, each of which held between ten and 15 people.
The gang would also use another vehicle to go ahead of the vans to check the coast was clear, and had rented apartments in Vienna so drivers could rest between trips, said Franz Prucher, police chief in Lower Austria.
Austria has become a major transit route for hundreds of thousands of migrants and refugees heading for northern Europe this year.
It stepped up checks for people-smugglers after the bodies of 71 migrants including four children were found in an abandoned truck on a motorway near Vienna in August.
"The smugglers will continue to keep us busy in the coming months," Mikl-Leiter told a news conference, calling for the European Union to establish "legal routes to Europe".