The California Gully man, 25, who cannot be named for legal reasons, pleaded guilty in Bendigo Magistrates Court on Friday to three charges of contravening a family violence intervention order and one count of theft.

The court heard the man entered his ex-partner's home while she slept in April this year, took her mobile phone so she couldn't call police and removed their 15-month-old child from his cot.

When the woman woke, he told her he had cancer and was going to keep their baby until the cancer killed him. 

The man then began making threats to the woman and searching the home before going outside to search the garden and being locked out of the house.

The court was told the incident occurred just four days after a temporary protection order was made. 

A final safety intervention order was made in June and was breached twice, police prosecutor Leading Senior Constable Chris Jones said.

He said the man sent the woman numerous text messages including threats to take their child and report her alleged drug use to the Department of Human Services.

The court heard the offending breached a community corrections order received in May this year for charges including unlawful assault, intentionally causing injury and recklessly causing injury and possessing a drug of dependence.

Defence lawyer Tim Tyler told the court his client had turned to drugs and alcohol about two years ago after he stopped sports training.

Mr Taylor said the man was experiencing mental health issues and described his behaviour as irrational, bizarre and disturbing.

He said although his client had previously appeared before the courts, his mental health had not been thoroughly investigated.

Magistrate Kay Robertson said she would need more information about the man's mental health before being able to sentence.

Ms Robertson ordered a pre-sentence report, including an assessment for possible acquired brain injury from a sports injury.

The case was adjourned for sentencing in November.