The attack overnight Sunday was the third since the show by Italian-German photographer Luigi Toscano was installed in early May.
Faces were cut out of around 80 portraits, an AFP photographer said. Over the past two weeks, others have been daubed with swastikas or slashed with knives.
Bellen said he was "deeply worried" over the assaults on the show honouring victims of Nazism.
"I know that the overwhelming majority of Austrian society totally rejects the atrocities committed by the Nazis," Bellen said in a statement. "That some cannot see the truth and solemn reminder shown by these photos is crushing," he said.
Toscano said he was "devastated" by the attack, the first on 13 such installations around the world.
"There's been vandalism which hasn't been politically motivated, but nothing of this proportion," Toscano told AFP. "This is right-wing radicalism."
Austria's Forum Against Anti-Semitism tallied 503 anti-Semitic acts in the country in 2017, twice the figure from 2014.