A young man has been charged with murder after a heated dispute over the use of a computer ended with his father allegedly stabbed to death in Sydney's southwest.

Police allege Daniel Chapman, 20, stabbed his father during an argument over dinner at the family's Moorebank home at 8.40pm yesterday.

"I believe the son uses it (the computer) quite regularly and when he's asked to come to the dinner table he continued on the computer," Detective Chief Inspector Ken Hardie said.

“I believe that’s what the argument might have been over.”

Police take a computer away from the scene. (9NEWS)

Paramedics tried to save 56-year-old Stephen Chapman, but he died on the way to hospital.

Mr Chapman's wife was frantic and too distressed to call triple zero and instead sent her son over the road to a neighbour’s house to call for help.

Daniel, a former Moorebank High School student, was remanded in custody today, and had his bail formerly refused.

He will face Campbelltown Court again on Wednesday.