An elderly man has died after a break-in at his home in Sydney's southwest.

The 78-year-old man and his wife returned to their Moorebank home at midday (AEDT) last Monday to find a man in the house.

The woman left the room and returned to find her husband on the floor. He was taken to Liverpool Hospital and died on Tuesday, police say.

A 53-year-old Fairfield man has been charged over the break in.