Police say they believe a man found hanged at a changing room in Tuen Mun on Thursday had attempted to murder his daughter before taking his own life.

Officers said they were called to the flat at Botania Villa on Fuk Hang Tsuen Road at about 6pm by the wife of the 66-year-old man. The wife, 64, said he had assaulted their 39-year-old-daughter and had left the home after she intervened.

Police arrived to find the daughter injured but conscious. She was rushed to Tuen Mun Hospital, where she received treatment for neck and chest wounds.

Officers found the suspect about an hour and a half later hanging with a belt in a changing room at the development's clubhouse. He was declared dead at Tuen Mun Hospital.

Police say their initial investigations showed that the man attempted to cover his daughter's head with a plastic bag before his wife intervened.

The force said it had seized a plastic bag, a belt and what officers described as a will note in connection with the case. A post-mortem will be carried out.

It's being treated as a case of attempted murder and suicide. The Tuen Mun district crime squad is investigating.

The Social Welfare Department said it is highly concerned about the tragedy, and said it will reach out to the family as soon as possible to offer emotional counselling and assistance.