A series of harrowing cases of allegations of medical negligence, including the death of novelist Chimamanda Ngozi Adichie's 21-month-old son, has ignited a fierce debate about patient safety and systemic failures within Nigeria's healthcare system.

The family of the internationally acclaimed author says her young son, Nkanu Nnamdi, died last week at a private hospital in the main city, Lagos, following a short illness.

They allege the child was denied oxygen and excessively sedated, leading to cardiac arrest.

The hospital extended its "deepest sympathies" but in a statement denied any wrongdoing, stating its treatment met international standards.

The Lagos State Government has ordered an investigation into the death, as public outrage spread over the state of healthcare in Africa's most populous country.