Police have charged a man with murder over the bashing death of a 60-year-old man found unconscious on a western Sydney street.

Police believe the Valley Heights man, who has yet to be formally identified, died after he was attacked on a street in Parramatta on Thursday night.

He was discovered lying unconscious on the Church Street Mall at 9.30pm (AEDT) and taken to Westmead Hospital, where he died a short time later.

A post-mortem examination has yet to be carried out but it's believed the man may have suffered head injuries.

A police spokeswoman on Saturday confirmed a man, in his late 40s, was arrested late on Friday night and charged with the 60-year-old's murder.

The alleged killer will face Parramatta Bail Court on Saturday.