A judge has told an accused murderer she might struggle to prove self-defence despite claims of her alleged victim's history of violence.
Nikita Kirby, 31, was denied bail by Judge Helen Wilson in the NSW Supreme Court on Thursday due to a lack of evidence that she acted in self-defence and concerns she could interfere with witnesses.
She is accused of stabbing to death former partner Scott Wallace, 37, at her sister's home in the southern Sydney suburb of Matraville in late May.
Her lawyer Talal Krayem told the court she was a victim of ongoing domestic violence by Wallace, citing an alleged stabbing incident in 2021.
The court heard a relative of Kirby's, who was in the house at the time, did not see any aggression from Wallace before she stabbed him.
But it was not until later that same relative told police that Kirby's mother said it was self-defence "so it was", the court was told.
"(She) wasn't present at the time and so her opinion as to self-defence will not be admissible," Justice Wilson said.
Prosecutors told court that during a phone call at the time of the incident, Kirby threatened her sister into coming home and said "this motherf***er is gonna die" in her house.
"On what's available to this court, at this early stage, it doesn't seem like self-defence strongly arises, if it arises at all," Justice Wilson said.
Proposed bail conditions could allow Kirby to interfere with witnesses as she would be living with her mother and have contact with her sister, the judge said.
Another relative of Kirby's called police after the phone call, a move the accused killer had abused her over, the court heard.
Other concerns in refusing bail were a history of charges for domestic violence and non-compliance with bail conditions.
The case is due to proceed to trial in mid-late 2025.
1800 RESPECT (1800 737 732)
Lifeline 13 11 14