Authorities in Austria, Hungary, Slovakia, the Czech Republic and Romania detained a total of 205 members of the organised crime gang, which specialised in smuggling mostly Syrian refugees to Germany, France, Belgium and the Netherlands, he said.
More than 36,100 people are believed to have been taken across borders since the beginning of last year, with Vienna serving as the hub for the operation.
The gang is thought to have taken in more than 152 million euro ($A230 million).
A 28-year-old Romanian, the suspected leader, was detained in that country on May 4.
Austrian police also uncovered a number of workshops in and around Vienna where vehicles were converted for ferrying the migrants, seizing about 80 vehicles.
Last October, two bodies were found in a vehicle carrying about 30 people in Austria near the border with Hungary.
Austrian police said the transport had been carried out by the suspected gang leader.
Another suspected gang was subsequently detained in Latvia.
A further suspect, who fired on Austrian troops in January, is reported to have been detained in Hungary.
Karner pointed to the scope of the arrests in justifying his recent decision to extend controls on Austria's borders with Hungary and Slovenia - all three are members of the Schengen free travel area.
"Gangs are at work for whom human life is completely irrelevant," he said.