Police on Tuesday laid a holding charge of murder against a 51-year-old man on suspicion of stabbing his wife to death and setting fire to their Tuen Mun flat.

Officers were called to a unit in Ting Fuk House, On Ting Estate, over a small fire at around 7am on Tuesday.

A 50-year-old woman was found unconscious with knife wounds and burns. She was pronounced dead at Tuen Mun Hospital.

The suspect, who had hand injuries, was arrested at the scene.

Chief inspector Chong Yuen-na later told reporters that the suspect was diagnosed with schizophrenia 10 years ago and had been receiving long-term psychiatric treatment.

“Neighbours and relatives say they often argued over small issues. On Tuesday morning, a neighbour heard the woman screaming and crying from the unit,” she said.

"It is believed that during the argument, the man suffered a psychological episode and attacked the deceased with a knife."

A butcher’s knife believed to have been used in the attack, along with a lighter and some burnt papers, were seized from the flat.

The suspect is due to appear at Tuen Mun Magistrates’ Courts on Wednesday.