The body believed to be that of suspected poacher Alois Huber, 55, was found after police rushed the home near Melk at dusk, the BBC reported.
The network said Austria's Krone newspaper reported Huber's body was found in a "secret room" in the farmhouse. There were unconfirmed reported Huber had set himself on fire, the BBC said.
Several dozen police officers had flooded the suspect's farm, surrounding the house where he was holed up with numerous weapons, the Austrian Press Agency reported. A single shot fired from the farmhouse at 5:30 p.m. local time had been the last sign of life inside, the news agency said.
The incident began late Monday when police, who were conducting a surveillance operation for poachers, stopped the suspect's car at a roadblock. The man smashed his vehicle into the barrier and began shooting.
One officer was fatally wounded. The man then shot and killed the driver of a Red Cross truck and wounded a second police officer before fleeing on foot, the APA said.
He then fired at another patrol car, killing a second officer and taking another officer hostage. He fled to his farm in the car with the hostage, who was later found dead in the vehicle.
Once inside his home, the gunman, apparently alone, fired more shots at police, the APA said.
Attempts by family members to convince him to surrender had been unsuccessful, the news agency said.
Smoke was seen coming from the home.