Slain NSW cop's family brace for appeal

The family of a decorated NSW policeman stabbed to death in the line of duty in 2012 are bracing for his convicted killer's appeal.

As a legal challenge by Inspector Bryson Anderson's convicted murderer Mitchell Barbieri was set down for June, Insp Anderson's brother Warwick said the family would follow the case "every step of the way".

"Bryson can't be here so we're going to ensure that his interests are protected and represented," Mr Anderson told reporters outside the Supreme Court on Thursday.

"As a family, we're looking forward to the end of it."

Barbieri is appealing the severity of his 26-year minimum sentence for fatally stabbing Insp Anderson in the chest with a hunting knife at a rural property in Sydney's northwest in December 2012.

It followed a protracted siege at Barbieri's Oakville property after Insp Anderson responded to reports of arrows being fired.

An appeal hearing has been scheduled for June 21 and is expected to include further evidence, including a mental health report.

Barbieri's mother Fiona is serving a minimum of seven years for Insp Anderson's manslaughter.

A 2014 sentencing hearing was told Fiona Barbieri suffered paranoid schizophrenia and before Insp Anderson's death had lived with her son in squalor with no electricity.

She had believed she was being persecuted by police and political leaders, and after the stabbing said Insp Anderson had deserved to die.