The World Health Organization (WHO) says a report on North Korea's health system by Amnesty International is unscientific and outdated.
Rights watchdog Amnesty said North Korea was failing to meet its people's most basic healthcare needs.
Amnesty's report is based on interviews with 40 North Korean defectors and foreign health care workers.
In April, the WHO's director visited North Korea and said its health system was the envy of the developing world.
WHO director-general Margaret Chan said the country had "no lack of doctors and nurses".
North Korea has faced critical food shortages and relies on international aid following famine in the 1990s which killed up to one million people.
The country is politically isolated and subject to UN sanctions, which were tightened last year after Pyongyang carried out missile and nuclear tests.
Amnesty's report, The Crumbling State of Health Care in North Korea, was released on Thursday.
It describes barely functioning hospitals, poor hygiene and epidemics made worse by widespread malnutrition.
Many people were also too poor to pay for treatment, the report says. It also cites WHO figures indicating Pyongyang spends less than $1 (£0.65) per person on healthcare a year.
Pyongyang says it provides free healthcare for its people, but witnesses told Amnesty they had had to pay for all services for the past 20 years.
BBC News
