A son has been denied bail after being accused of fatally stabbing his father inside the family home in Sydney's west last night.

NSW Police were called to Clouta Place, Emu Plains, at 6.45pm yesterday and said 58-year-old John Clark was found with multiple stab wounds to his upper body.

He was treated by NSW Ambulance paramedics but died at the scene.

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The man's son, Evan Davis Clark, 30, was arrested at the scene and taken to Penrith police station.

He was later charged with one count of domestic violence murder, police said this morning, as investigators continued to pulled bags of evidence from the home.

Videos posted to social media showed more than a dozen police cars, ambulances and the police helicopter responding to the incident.

"It was probably about 15 cop cars and everything there, so pretty hectic," a neighbour told 9News.

Police said there was a history of domestic violence allegations, however, there were no reports in the past few years.

"For someone's family to start off the long weekend in such tragic circumstances is very tough," Acting Superintendent Michael Cantrell said.

Residents told 9News that the family have been living at the home for more than 40 years.

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"[It is] a quiet street, you would never think something like this would occur here," a resident said.

"There were no indications that something like this would occur up there."

"I can't say I would have expected something like this."

Clark appeared in court today, saying he "just wants to do the time" as he was denied bail.

His lawyer raised concerns about his mental capacity as he spends at least the next two months behind bars.

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

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