Low availability and high prices are impeding access to medicines in developing nations, a report warns today.

The study, carried out by the World Health Organisation and Health Action International, says that as public sector medicine is difficult to come by patients are forced to purchase more expensive medicines from private clinics.

The high price of medicines is thought to be the key reason why they account for up to 60% of health spending in developing countries, compared with 18% in the richer countries of the Organisation for Economic Co-operation and Development.

Up to 90% of the population in developing countries purchased medicines through out-of-pocket payments, making medicines the largest family expenditure item after food.

The research shows that private sector patients in some poorer countries were paying between nine and 25 times the international norm for the lowest-priced generic medicines. The report, published by The Lancet today, says that treatments for acute and chronic illness were largely unaffordable in many countries.

The report states: "As a result medicines are unaffordable for large sections of the global population and are a major burden on government budgets. Increased emphasis should be placed on reducing the cost of these medicines in the light of the high burden of non-communicable diseases."

The researchers said the "consistently low" availability of medicines in the public sector could be due to products failing to make it on to national essential medicines lists, inadequate funding, lack of incentives for maintaining stocks and inefficient distribution systems. Some medicines could even be being sold on privately, the researchers claimed.

They suggest the increased use of cheaper generic medicines.