Murdered man's family in 'nightmare' over killer appeal

The Court of Appeal in Brisbane on Tuesday heard submissions about whether to overturn Wegener's conviction.

Mr Suttie's sister, Jody Proctor, said outside court that the trauma of his death had returned due to the appeal application.

"We have only just tried to piece our lives back together and then we are brought back here ... it's like living in a nightmare again," she said.

The original trial heard Wegener responded aggressively to a greeting from the 37-year-old Mr Suttie as their respective groups passed in a park south of Brisbane in August 2018.

The late-night encounter at Woodridge quickly escalated and Wegener produced a knife with "scalpel-like" sharpness, slashing at Mr Suttie's face and then throat.

Mr Suttie died after a severe cut to an artery despite his son's efforts to save him.

Zac Elder - then aged 19 - took his shirt off to try and stop blood spurting out of his father's neck.

Mr Suttie's life support was turned off days later after multiple organ failure caused by severe blood loss.

Benjamin Suttie died after being stabbed in the neck. (HANDOUT/QUEENSLAND POLICE)

Defence barrister Andrew Hoare told the Court of Appeal the prosecutor at the trial had unfairly damaged his client's character before the jury by using impermissible evidence.

"An association with a drug user and a drug dealer, both of which, the second clearly, imply the commission of serious crimes," Mr Hoare said.

Mr Hoare said the prosecutor at trial had no justification to cross examine Wegener about his relationship with a known drug dealer.

Justice Peter Davis asked Mr Hoare if the trial judge's directions to the jury would have overcome the issue of irrelevant evidence around Wegener's character.

"It was insufficient at the time it was given as the damage had been done," Mr Hoare said.

Crown prosecutor Mark Green told the Court of Appeal the drug dealer association did not affect the trial's outcome as the jury accepted eyewitness and forensic evidence that Mr Suttie was slashed multiple times.

"There is no miscarriage of justice. The jury had a very strong focal point in the evidence of the circumstances of the slashing," Mr Green said.

Justice Davis ordered a transcript of the hearing and reserved the Court of Appeal''s judgment to be handed down at a later date.