"Paramedics were called to the farm this morning at [08:00] and when they arrived on scene they were faced with absolute carnage," said Netcare 911 spokesperson Chris Botha.
He said the murders at Plaas Poortjie Farm, located between Senekal and Steynsrus, appeared to have taken place late on Tuesday night.
"The male, aged 65, and his 60-year-old wife had passed away during the night due to the severe trauma they had sustained."
Sergeant Majang Mosupa said no arrests had been made.
She said the generator on the farm apparently went off on Tuesday night and the woman went outside to investigate.
Someone stabbed her. She and her husband were then shot.
Mosupa said police did not know the motive for the crime but a Chevrolet belonging to the couple's daughter had been stolen from the farm.
A case of murder was being investigated.