Emerging Asian economies, led by China, are challenging world leaders North America, Europe and Japan in scientific research and development, said a United Nations report published on Thursday in Paris.

"The most remarkable trend is to be found in Asia, where gross expenditure on R&D has grown from a world share of 27.9 percent in 1997 to 31.5 percent in 2002," according to the 2005 Science Report, issued by the UN Educational, Scientific and Cultural Organisation (UNESCO).

Based on a wealth of data on science and technology development around the world, the report said the trend is largely driven by China, whose expenditure on R&D was 1.23 percent of its GDP in 2002, up from 0.83 percent in 1999, with priority given to information technology, biotechnology, and new materials technology, among others.

In 2002 China employed 810,000 researchers, 163,500 more than Japan, said the report written by an international team of independent experts.

The comprehensive introduction to the document highlighted that one of the new trends affecting science and technology worldwide is the new players' ability to make their mark on science and research, namely Turkey, China and a few others in Asia, Central and Eastern Europe.

Despite the challenge, North America still accounted for 37 percent of the 830 billion U.S. dollars world expenditure on R&D in 2002, slightly down from 38.2 percent in 1997. Europe also saw a diminishing share of the spending, down from 28.8 percent in 1997 to 27.3 percent in 2002. The remaining less than five percent were shared by Latin America and the Caribbean, Oceania and Africa.

The 2005 Science Report is the fourth one issued by UNESCO. It was last updated in 1998.