Sydney cousin stabbing conviction quashed

A Sydney woman jailed after a jury found her guilty of stabbing her cousin to death in a fight over a luxury car has had her conviction quashed on appeal.

The NSW Court of Criminal Appeal on Tuesday also ordered a retrial for Katherine Abdallah for the manslaughter of 21-year-old Suzie Sarkis in 2013.

Abdallah's Supreme Court trial heard the cousins had been fighting over Abdallah's new $184,000 Mercedes before she armed herself with two knives and killed her younger relative at her Brighton-Le-Sands townhouse on February 9, 2013.

Abdallah was sentenced to a non-parole period of six years and nine months in May 2018 after challenging her original manslaughter sentence of eight years and three months that was handed down in 2015.

The 38-year-old will be arraigned at the Supreme Court on February 14.