Police say if the stabbing hadn't occurred within 100m of Wollongong Hospital, the victim's injuries could have been fatal.

Unanderra man Timothy Marskell allegedly stabbed his brother  during the altercation, before leaving the scene and attempting to dispose of the evidence.

The victim was left with his intestine protruding through the wound and amassed on the outside of his stomach. 

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Marskell appeared in Wollongong bail court on Saturday, charged with wound person intend to cause grievous bodily harm.

Court documents said both the 39-year-old and his biological brother Daniel Bonacina, 43, are on the methadone program and attend Bungora Methadone Clinic.

On Friday, Marskell picked up his sibling at another Unanderra address and then drove to the clinic.

At 7.39am, Marskell parked the vehicle behind the clinic, and they walked east along Urunga Parade.

As they reached the corner, the pair began arguing over their methadone, which escalated into a physical altercation.

During the incident, Marskell allegedly produced a pocket knife with a 14cm blade, and stabbed his sibling in the left side of his abdomen.

With the assistance of a witness, Bonacina crossed the road and entered Wollongong Hospital, where he was immediately treated and rushed to surgery.

Court documents revealed that the incident was captured on CCTV footage.

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Meanwhile, Marskell walked back to his vehicle without offering any assistance and drove off.

Police allege Marskell returned home, changed his clothing and started a small fire in his yard in an attempt to dispose of evidence.

Police arrived at the home as the fire was lit.

Marskell attempted to evade police, but after a short time was arrested and taken to Wollongong Police Station, where he refused to answer police questions.

A warrant was granted and police located clothing, shoes and the knife believed to have been used during the offence.

Police also spoke with Bonacina at the hospital, who at the time the court documents were written was in a stable condition.

"The injuries inflicted on the victim were serious in nature, and if the victim was not within 100m from the Wollongong Hospital could have been fatal," the court documents said.

During Saturday's bail court, Marskell was described as a "man with a history of violence", and broke down in tears when appearing via video link.

Marskell was bail refused to reappear on Wednesday.