Health systems have so far responded in an "inadequate and naive" way to social changes such as globalisation, urbanisation and ageing, and wide inequalities persist between and within countries, the WHO said in its Annual Health Report.
"Business as usual for health systems is not an option," the WHO said.
"It is clear that left to their own devices, health systems do not gravitate naturally towards the goals of health for all," the report said.
Annual government expenditure on health varies from as little as 20 dollars per person (15 euros) to well over 6,000 dollars, while the difference in life expectancy between the richest and poorest countries now exceed 40 years, the WHO said.
On a national level, the WHO highlighted the striking example of under-five mortality rates in the Kenyan capital Nairobi. In a high-income area, the rate is below 15 per thousand, while in a slum in the same city, the rate is 254 per thousand.
"Rather than improving their response capacity and anticipating new challenges, health systems seem to be drifting from one short-term priority to another, increasingly fragmented and without a clear sense of direction," it further charged.
Health care is often delivered according to a model that concentrates on diseases, high technology, and specialist care, with health viewed as a product of biomedical interventions and the power of prevention largely ignored, the WHO said.
A "command-and-control" approach to disease, focused on short-term delivery, is fragmenting service delivery while some governments have adopted an overly "laissez-faire" approach leading to unregulated commercialisation of the health sector, it noted.
For 5.6 billion people in low- and middle-income countries, more than half of all health care expenditure is through out-of-pocket payments, the WHO said.
"These trends fly in the face of a comprehensive and balanced response to health needs," it warned.
The WHO released its report on the 30th anniversary of a seminal conference in Almaty, now the principal city of the independent state of Kazakhstan, and then the capital of the former Soviet republic of the same name, which sought to tackle political, social and economic health inequalities.