A farmer and his wife were assaulted by two robbers on their farm near Fouriesburg in the Free State, police said on Thursday.

Sergeant Mmako Mophiring said the couple were watching television at about 8.30pm on Wednesday when two armed men entered the house.

"Apparently they entered the house through the back door which was not locked."

Mophiring said the couple was assaulted and the robbers demanded firearms and money.

He said the woman was allegedly sexually assaulted. She was being treated at the Hoogland Medi-Clinic hospital in Bethlehem.

The men fled in a white Citroen with registration number SKK954GP.

Mophiring said police were looking for the stolen vehicle and the men, believe to be between 30- and 50-years-old.