David John Cox, 53, had pleaded guilty in the Ballarat Magistrates Court to four counts of intentionally causing injury.

The court had heard Cox was "out of his mind" during the offending in February this year and had been diagnosed with chronic paranoid schizophrenia.

Cox struck his partner with an iron bar and assaulted the woman numerous times with his fists over a four day period before she was able to leave the house and seek medical attention. The woman was badly bruised.

Cox had also been using cannabis and alcohol at the time, the court heard.

Magistrate Kay Robertson described the offending as "very serious".

"I note that you're now saying it wasn't your fault," she said.

Ms Robertson sentenced Cox to one year and three months in jail with a non-parole period of six months.

Cox has already served 145 days in custody.