The asylum-seekers, from Afghanistan, Iraq and Pakistan, included 16 children, the youngest just five months old, according to local police.
Among them was also an eight-months pregnant woman.
They had been locked inside the windowless back of the lorry for more than 12 hours when police found them, and had resorted to making small air-holes in the sides so they could breathe.
The pregnant woman had already fainted by the time police were able to free her, and several of the men collapsed when they were released.
“This is by far the worst case of trafficking [we’ve seen],” Johann Baumschlager, a spokesman for Lower Austria police, said. “Even experienced officers were shocked.”
Police stopped the Hungarian-registered lorry on the A1 Autobahn near near Sankt-Pölten on Saturday, after noticing that it was heavily overloaded.
The driver abandoned the vehicle with the migrants still packed inside, and fled before police could arrive. He is still on the run.
The Red Cross provided the asylum-seekers with food and water.
Two of those on the truck requested asylum in Austria, and six of the children, who were travelling unacompanied, were taken into care. The rest were allowed to continue theri journey.
Most were believed to be on their way to Germany or Scandinavia, where many hoped to meet relatives.
Austria lies on one of the main overland routes to Europe for migrants, and just hours later police stopped another vehicle with 38 asylum-seekers packed in the back.
“Nearly every day we stop these trafficking transports,” Kontrollinspektor Baumshclager told NBC. “It’s a miracle no one has died yet.”
Under EU rules, refugees are supposed to claim asylum in the first member state they reach.
But Italy and Greece, the countries where the majority arrive by boat, are overwhelmed, and migrants say they are frequenly encouraged to move on.
Other countries, such as Germany, are known to be more welcoming, leading asylum-seekers to try their luck around Europe.