Police on Wednesday launched an investigation after a 90-year-old man plunged to his death from a building on a public housing estate in Sha Tin after allegedly attacking his wife.

Officers were called to a flat at the Ming Shun Building on the Jat Min Estate, at about 5am where they found the 75-year-old woman, who had suffered head wounds.

She told officers she'd been attacked by her husband, who later plunged to his death from the building. He was certified dead at hospital.

The woman was taken to hospital for treatment for her injuries.