A milk farmer was attacked in his home in Bronkhorstspruit after a tree stump was thrown through his bedroom window, Gauteng police said on Wednesday.

"There were five suspects. They went to his plot and threw a tree stump through the window and attacked the farmer," spokesman Johannes Japhta said.

"A couple staying in the house heard the screams. The husband of the couple fired a shot into the air and the attackers ran away. They entered the 64-year-old man's room and they found him on the floor injured."

The farmer was sent to hospital for treatment.

Japhta said police could not establish whether all five attackers were armed, but according to witnesses, some were.

The attack happened around midnight on Monday. The man's cellphone was taken. It was unclear whether anything else was missing.

"The investigation is ongoing and no arrests have been made. Police are investigating a case of attempted murder and house robbery."