Police have arrested a 50-year-old man on suspicion of murder over the death of a man at a residential care home in Yuen Long.

Police had not initially suspected foul play after being called to the scene by a staff member on Monday afternoon.

A 54-year-old man was found unconscious on the ground with no superficial injuries at the home on Long Wo Road, and was later certified dead at Pok Oi Hospital.

But after conducting initial investigations, authorities later said they suspected a physical altercation had taken place, and reclassified the case from 'death on arrival' to murder.

The force said in a statement that post-mortem examinations will be conducted to ascertain the cause of death.