A man critically injured in an assault at his Western Heights, Rotorua home in September has died.

The man and his wife were seriously assaulted on September 23, said a police spokesperson in a statement released today.

"The woman passed away on the evening of October 5 and sadly her husband has now also died, passing away in hospital yesterday."

Police said a 52-year-old man who was arrested and charged with murder in relation to a linked incident at an Utuhina property will now be facing murder charges in relation to all three deaths.

The man is remanded in custody and is scheduled to reappear in Rotorua High Court on 1October 18.

"Police are not seeking anyone else in relation to the three deaths."