Troy Michael Kennewell, 19, and his girlfriend were at a Kambah house party on Saturday night when they left and fought about allegations of infidelity, court documents suggest.

The argument caught the attention of a passerby, who later told police he had heard a woman scream on Kingsmill Street.

He walked up to the fence and looked over and saw a man push a woman in the chest and the woman fall to the ground.

He approached the man, who police allege was Mr Kennewell, who told him, "she f---en cheated on me".

The good samaritan said he replied, "so what?"

After that he said he felt three pushes from the man before he ran off.

"He stated that his arm went cold and at first he thought he had been punched," the documents say.

"He then saw blood on his shoulder and realised he had been stabbed."

He said he felt like he was going to die and it was not until paramedics arrived he felt he may survive.

Police say when they arrived they found a man with stab wounds to his wrist, and to his shoulder and abdomen which were "bleeding profusely".

Officers say during an inspection of the crime scene they found a bag with Mr Kennewell's driver's licence and a gold flick knife. The knife did not have any visible blood on it.

Mr Kennewell, a student at CIT, later went to the police station and said he had been drunk and blacked out the night of October 21.

He was later arrested.

Prosecutors on Tuesday opposed Mr Kennewell's release on bail, citing a risk he would fail to appear at court and interfere with evidence and witnesses.

The prosecutor noted the knife apparently used in the alleged attack had not been found.

He said the difficulty in releasing Mr Kennewell was drafting bail conditions that would mitigate the risks posed by the young man.

"We've got an angry, drunk and violent young man who responds to a good samaritan by stabbing him in the chest," the prosecutor said.

But the man's defence solicitor said this was the man's first time in custody and he had voluntarily gone to the police station, where he was subsequently arrested.

She said he had a limited criminal history and no history of breaching bail or failing to attend court.

Magistrate Karen Fryar said she would grant Mr Kennewell bail to live at his mother's house in Young, NSW.

She said given the allegations as set out in the police statement of facts Mr Kennewell was lucky the incident was not more serious than it was.

Ms Fryar imposed bail conditions including that he report three times a week to police and not drink alcohol.

He is also not to contact the alleged victim or witnesses or enter Kambah.

Mr Kennewell is charged with negligent act causing grievous bodily harm and intentional wounding.

He has not entered pleas.

The alleged victim has had surgery and is in a stable condition, the documents say.

The injury to his abdomen was deemed non-life threatening but the man required stitches to the deep cut on his left deltoid.

He will require at least six weeks of physio.

The case is next due in court on November 14.