A man has been charged with two counts of murder after a woman and her partner were allegedly stabbed to death in north-west Sydney this morning.

Police are investigating whether the incident is a love triangle gone wrong, with the 47-year-old accused a former partner of the 38-year-old woman.

Just before 5am, emergency services were called to a home in Illabo Street in Quakers Hill after reports of a disturbance.

A woman is dead and a man fighting for life after an apparent stabbing in Quakers Hill, Sydney. (9News)

Police found a 30-year-old man on the footpath who had suffered apparent stab wounds to his stomach and hands.

The man was taken to Liverpool Hospital in a critical condition but he died from his injuries later this morning. He is yet to be identified.

The woman, Anasaini Waqavuki, was found dead inside the home, allegedly stabbed to death in the kitchen.

Police said Waqavuki was previously in a relationship with the alleged killer, and they are working on the belief the incident is domestic violence-related.

Anasaini Waqavuki, 38, was found dead inside the home, allegedly stabbed to death in the kitchen. (9News)

Superintendent Jason Joyce said the scene was challenging for police and paramedics.

“It was a very traumatic incident,” he said.

“Very sad in terms of the time of the year, my sympathy goes out to the family of the deceased.

“Very confronting for my police and emergency services that attended. Obviously not a nice thing to see.”

Neighbours recalled hearing screams coming from the home in the early hours of the morning but were shocked by the news.

Superintendent Paul Joyce said the suspect was previously in a relationship with the woman. (Nine)

“They seemed to be happy, she was always laughing, they seemed like a normal, happy family,” neighbour Wayne Spalding said.

The 47-year-old man was arrested after he handed himself in to Blacktown Police Station about 5.30am and was charged with two counts of murder this evening.

He’s been denied bail and will front court tomorrow.

Multiple crime scenes have been declared, including at the Illabo Street home and at a service station in Woodcroft, where a knife used in the alleged attack was located.

Multiple crime scenes have been declared, including at the Illabo Street home and at a service station in Woodcroft, where a knife used in the alleged attack was located. (9News)

A crime scene has also been declared at a home in Blacktown, where the suspect lives, and at Liverpool Hospital.

Police have urged any witnesses or anyone with CCTV or dashcam footage between 4.30am and 5.30am to contact Crime Stoppers.

Support is available from the National Sexual Assault, Domestic and Family Violence Counselling Service at 1800RESPECT (1800 737 732).