A member of the family, Barrister Wabueze Amadi, who confirmed the death said he passed on at about 3.45pm at the hospital.
Amadi was one of the greatest Nigerian Authors of all time. A master of words, who was best known for the masterpiece - The Concubine.
the late author hails from the first generation of Nigerian writers, in the league of the likes of Chinua Achebe, JP Clark, Cyprian Ekwensi and Christopher Okigbo.
His other books include Sunset in Biafra, Peppersoup, The Slave and The Road to Ibadan. He died in hospital in the oil city of Port Harcourt.
A physics and mathematics graduate of the University of Ibadan, he also joined the Nigerian army and continued serving in it during the civil war, despite coming from the Niger Delta, which was part of the breakaway state of Biafra.
Many Nigerians grew up reading his first novel The Concubine, which focuses on love in a southern village, and how it came into conflict with traditional life. He will best be remembered for the way he portrayed life in rural Nigeria and for the tricky plots and changing views in his novels.
It spawned Amadi's only non-fiction work, Sunset at Biafra, in 1973, detailing his experiences during the war.
Though many books have written on the conflict, his work stands out for accuracy, neutrality and conciseness.